Very Dense Wavelength Beam Combined Laser System

ABSTRACT

Apparatus, systems and methods to spectrally beam combine a group of diode lasers in an external cavity arrangement. A dichroic beam combiner or volume Bragg grating beam combiner is placed in an external cavity to force each of the diode lasers or groups of diode lasers to oscillate at a wavelength determined by the passband of the beam combiner. In embodiments the combination of a large number of laser diodes in a sufficiently narrow bandwidth to produce a high brightness laser source that has many applications including as to pump a Raman laser or Raman amplifier.

This application claims under 35 U.S.C. § 119(e)(1) the benefit of thefiling date of U.S. provisional application Ser. No. 62/519,113 filedJun. 13, 2017, the entire disclosure of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION Field of the Invention

The present inventions relate to systems, methods and apparatus forcombining laser beams to provide laser beams having the propertiesuseful in performing laser operations such as welding, cutting, surfacetreating, surface cladding, 3-D printing, and as a pump source for otherlaser systems.

There is a strong need to process materials that cannot be processedwith today's IR lasers because of the high reflectivity of the materialin the IR. While blue laser light can be strongly absorbed by materials,which are highly reflective in the IR, they have not found generalapplicability or utility for commercial laser operations. Currentlyavailable blue laser beams and systems are incapable of providing bluelaser beams that are of equal quality to IR laser beams, e.g., power,brightness, etc. It is believed that prior to the present inventions,blue laser beam systems were, for example, incapable of commerciallywelding thick materials such as copper, which are highly reflective inthe IR. Thus, with the exception of recent advancements by AssigneeNuburu Inc., building a visible wavelength laser of sufficientbrightness has evaded the industry for many years, frequency doublinghas been attempted with little commercial success due to the limitationsof the doubling crystals. Blue laser diodes by themselves are stillgenerally too low power to perform most, a wide range, if not all,commercial laser applications for operations on materials that arehighly reflective in the IR. Power levels for these blue diodes aretypically very low, with “high power” for these diodes generallyreferring to about 6 Watt (“W”). Moreover, conventional beam combinationmethods (spatial, polarization and discrete wavelength) are insufficientto build a blue laser with sufficient brightness to meet the needs ofthe industry. Spatial combination is limited in brightness by thephysical size of the micro-optics used to collimate the laser diodesource. Polarization combination (non-coherent) can only increase thebrightness by a factor of 2×. Wavelength combination is currentlyaccomplished by coupling a wavelength selective element such as a volumeBragg grating (“VBG”) to control the wavelength of the laser diodefollowed by a series of dichroic filters to combine the beams into asingle spatial beam with a wide bandwidth. This approach requires theuse of individual VBGs which is an additional cost to the system, aswell as increasing the size of the system. Coherent combination, whilecapable of building high brightness sources, is generally complex andtoo expensive to implement in a commercial system.

The terms “laser processing, “laser processing of materials,” andsimilar such terms, unless expressly provided otherwise, should be giventhe broadest possible meaning and would include welding, soldering,smelting, joining, annealing, softening, tackifying, resurfacing,peening, thermally treating, fusing, sealing, and stacking.

As used herein, unless expressly stated otherwise, “UV”, “ultra violet”,“UV spectrum”, and “UV portion of the spectrum” and similar terms,should be given their broadest meaning, and would include light in thewavelengths of from about 10 nm to about 400 nm (nanometer), and from 10nm to 400 nm.

As used herein, unless expressly stated otherwise, the terms “visible”,“visible spectrum”, and “visible portion of the spectrum” and similarterms, should be given their broadest meaning, and would include lightin the wavelengths of from about 380 nm to about 750 nm, and from 400 nmto 700 nm.

As used herein, unless expressly stated otherwise, the terms “blue laserbeams”, “blue lasers” and “blue” should be given their broadest meaning,and in general refer to systems that provide laser beams, laser beams,laser sources, e.g., lasers and diodes lasers, that provide, e.g.,propagate, a laser beam, or light having a wavelength from about 400 nmto about 500 nm, and from 400 nm to 500 nm.

As used herein, unless expressly stated otherwise, the terms “greenlaser beams”, “green lasers” and “green” should be given their broadestmeaning, and in general refer to systems that provide laser beams, laserbeams, laser sources, e.g., lasers and diodes lasers, that provide,e.g., propagate, a laser beam, or light having a wavelength from about500 nm to about 575 nm, and from 500 nm to 575 nm.

As used herein, unless expressly stated otherwise, the terms “red laserbeams”, “red lasers” and “red” should be given their broadest meaning,and in general refer to systems that provide laser beams, laser beams,laser sources, e.g., lasers and diodes lasers, that provide, e.g.,propagate, a laser beam, or light having a wavelength from about 600 nmto about 750 nm, and from 600 nm to 750 nm.

Generally, the term “about” as used herein, unless specified otherwise,is meant to encompass a variance or range of ±10%, the experimental orinstrument error associated with obtaining the stated value, andpreferably the larger of these.

As used herein, unless expressly stated otherwise, the terms “IR”,“infrared”, “IR wavelength” and “IR spectrum”, should be given theirbroadest meaning, and in general refer to systems that provide laserbeams, laser beams, laser sources, e.g., lasers and diode lasers, thatprovide, e.g., propagate, a laser beam or light having a wavelength >700nm, and greater than about 750 nm.

Relevant Art

Spectral beam combination of laser beams in a laser cavity has beenknown since 1993 (Papen et al, “Multiple-wavelength operation of alaser-diode array coupled to an external cavity, Optics Letters 18, 1441(1993)). However, it is believed that spectral beam combining of highpower blue laser diodes with a comb filter element positioned in anexternal cavity has not been demonstrated or disclosed prior to thepresent inventions.

The TeraDiode method is illustrative of the challenges of the art. Thismethod is based on the work of Hamilton et. al, and Sanchez et. al, anduses an external cavity arrangement and a grating to combine the outputsof n-laser diodes. The TeraDiode method however requires a very long (˜1m or more) external cavity because of the low dispersion of the gratingused to create the comb filter at the face of the laser diode.

Another concept, that has been unsuccessful at high power levels forspectral beam combination of laser diodes to improve the brightness ofthe laser diode array is a method where the wavelengths of eachindividual laser diode is locked via a grating structure which isinternal to the laser diode itself. The beam combination provides ameans to spatially overlap each of the individual laser diode beamsoutside of any common laser resonator cavity. This method of spectralbeam combination is complex, since the spatial beam combinationdielectric filter array must match the output wavelength characteristicsof each individual laser diode. Additionally, the laser diode structureis much more complex to fabricate due to the necessary inclusion of afeedback structure during the laser diode fabrication process. It isbelieved that fabricating the grating structure in a visible laser diodehas yet to be demonstrated.

This art has numerous failings. Significantly, and among other failings,this art does not teach or disclosed the spectral beam combining ofblue, and blue-green, green laser beams and red, or the spectral beamcombining of blue, blue-green, green laser diodes and red laser diodes.Additionally, it is believed that to the extent the art may teach ordisclose an external cavity, that cavity would be large and prone tothermo-mechanical instabilities. It is further believed that, amongother things, the art does not disclose a compact, stable system, and inparticular, such a system for the blue, blue-green, green and redwavelengths.

This Background of the Invention section is intended to introducevarious aspects of the art, which may be associated with embodiments ofthe present inventions. Thus, the forgoing discussion in this sectionprovides a framework for better understanding the present inventions,and is not to be viewed as an admission of prior art.

SUMMARY

Embodiments of the present invention overcome these long-standingproblems to provide high brightness visible wavelength laser beams, andin particular red, green and blue, and more particularly blue laserbeams having high brightness and sufficient power to perform commerciallaser operations on materials that are highly reflective in the IR, aswell as, improved performance on all other materials. Embodiments of thepresent inventions accomplish this, as well as, among other things, bygreatly simplifying the wavelength beam combination systems and methods

While laser diodes are becoming competitive with current fiber lasers,the low brightness of the diode laser beams has been a long-standingproblem, and prevents their wider acceptance and utilization. Inaddition, there has existed a long-standing and unresolved need forcompact and small laser systems that can provide high brightness laserbeams. The present inventions, among other things, solve these needs byproviding the articles of manufacture, devices and processes taught, anddisclosed herein.

Thus, there is provided a high power, high brightness laser system whichcomprises of the following: two or more individual high power laserdiodes; a common external cavity shared by two or more individual highpower laser diodes; collimating optics for creating parallel beams fromeach of the high-power laser diodes; a beam combination optics in thecommon external cavity which determines the wavelength of each laserdiode and aligns each laser diode to be co-linear and overlapping inspace; the spatial brightness of the laser source is n-times thebrightness of a single laser diode where brightness is defined as thecombined power divided by the aperture-divergence product.

Further there is provided these high power lasers, systems and methodshaving one or more of the following features: where the beam combinationoptic consists of the optical cavity formed from a set of opticalfilters that are used at the edge of either the low pass or high passend of the spectrum for a bandpass filter and an output coupler ormirror; operating in the 400-500 nm range with an output power of >1Watt and a beam parameter product of 0.1 mm-mrad or larger; operating inthe 500-600 nm range with an output power of >1 Watt and a beamparameter product of 0.1 mm-mrad or larger; operating in the 720-800 nmrange with an output power of >1 Watt and a beam parameter product of0.1 mm-mrad or larger; operating in the 800-900 nm range with an outputpower of >1 Watt and a beam parameter product of 0.1 mm-mrad or larger;operating in the 900-1200 nm range with an output power of >1 Watt and abeam parameter product of 0.1 mm-mrad or larger; operating in the 1200nm-1120 nm range with an output power of >1 Watt and a beam parameterproduct of 0.1 mm-mrad or larger; operating in the 1400-1500 nm rangewith an output power of >1 Watt and a beam parameter product of 0.1mm-mrad or larger; operating in the 1500-2200 nm range with an outputpower of >1 Watt and a beam parameter product of 0.1 mm-mrad or larger;operating in the 2200-3000 nm range with an output power of >1 Watt anda beam parameter product of 0.1 mm-mrad or larger; operating in the 3000nm-12000 nm range with an output power of >1 Watt and a beam parameterproduct of 0.1 mm-mrad or larger.

Yet further there is provided these high power lasers, systems andmethods having or providing an output laser beam with a beam parameterproduct of about 0.1 to about 10 mm-mrad, about 0.5 mm-mrad and larger;about 0.3 mm-mrad and larger, about 1 mm-mrad and larger, about 2mm-mrad and larger, about 3 mm-mrad and larger, and all values withinthese ranges, as well as larger and smaller values.

Still further there is provided these high power lasers, systems andmethods having one or more of the following features: where the beamcombination optic is a set of Volume Bragg Grating filters and one ormore volume Bragg gratings that redirects a portion of the opticalspectrum from an individual laser diode to be collinear with theprevious laser diode in the array and an output coupler which completesthe optical cavity; the brightness of the sum of the individual laserdiode beams after being directed by the volume Bragg gratings(s) is Ntimes brighter than that of an individual laser diode beam, with N beingthe number of laser diodes being combined; in a series of N volume Bragggratings, the points of maximum transmission through volume Bragggrating N coincide with the N-1, N-2, N-3, . . . 1^(st) peaks of thelasing spectra of the N-1, N-2, N-3, . . . 1^(st) laser diodes, whilesimultaneously providing maximum beam deflection of laser diode N.

In addition there is provided these high power lasers, systems andmethods having one or more of the following features: that operates onthe slow axis of the emitted laser diode light and the TE-mode ofindividual reflection volume Bragg grating(s); that operates on the fastaxis of the emitted laser diode light and the TE-mode of individualreflection volume Bragg grating(s); that operates on the slow axis ofthe emitted laser diode light and the TM-mode of individual reflectionvolume Bragg grating(s); that operates on the fast axis of the emittedlaser diode light and the TM-mode of individual reflection volume Bragggrating(s); that operates on the slow axis of the emitted laser diodelight and the TE-mode of individual transmission volume Bragggrating(s); that operates on the fast axis of the emitted laser diodelight and the TE-mode of individual transmission volume Bragggrating(s); that operates on the slow axis of the emitted laser diodelight and the TM-mode of individual transmission volume Bragggrating(s); that operates on the fast axis of the emitted laser diodelight and the TM-mode of individual transmission volume Bragggrating(s); that operates on the slow axis of the emitted laser diodelight and the TE-mode of individual reflection volume Bragg grating(s)fabricated in a single piece of material; that operates on the fast axisof the emitted laser diode light and the TE-mode of individualreflection volume Bragg grating(s) fabricated in a single piece ofmaterial; that operates on the slow axis of the emitted laser diodelight and the TM-mode of individual reflection volume Bragg grating(s)fabricated in a single piece of material; that operates on the fast axisof the emitted laser diode light and the TM-mode of individualreflection volume Bragg grating(s) fabricated in a single piece ofmaterial; that operates on the slow axis of the emitted laser diodelight and the TE-mode of individual transmission volume Bragg grating(s)fabricated in a single piece of material; that operates on the fast axisof the emitted laser diode light and the TE-mode of individualtransmission volume Bragg grating(s) fabricated in a single piece ofmaterial; that operates on the slow axis of the emitted laser diodelight and the TM-mode of individual transmission volume Bragg grating(s)fabricated in a single piece of material; and that operates on the fastaxis of the emitted laser diode light and the TM-mode of individualtransmission volume Bragg grating(s) fabricated in a single piece ofmaterial.

Still further there is provided a laser source comprising of thefollowing: one or more optical coatings that redirects a portion of theoptical spectrum from an individual laser diode at an angle up to 90°with respect to the laser diode output light propagation direction aftercollimation to a common output coupler; the optical propagationdirections in the near-field and far-field are defined by the round trippath in the cavity making them identical among two or more individuallaser diodes after being redirected by the optical coating(s); thebrightness of the sum of the individual laser diode beams after beingdirected by the optical coating(s) is N times brighter than that of anindividual laser diode beam, with N being the number of laser diodesbeing combined; in a series of N optical coatings, the points of maximumtransmission through optical coating N coincide with the N-1, N-2, N-3,. . . 1^(st) peaks of the lasing spectra of the N-1, N-2, N-3, . . .1^(st) laser diodes, while simultaneously providing maximum beamdeflection of laser diode N.

Further there is provided these high power lasers, systems and methodshaving one or more of the following features: that operates on the slowaxis of the emitted laser diode light and the TE-mode of individualreflection optical coating(s); that operates on the fast axis of theemitted laser diode light and the TE-mode of individual reflectionoptical coating (s); that operates on the slow axis of the emitted laserdiode light and the TM-mode of individual reflection optical coating(s);that operates on the fast axis of the emitted laser diode light and theTM-mode of individual reflection optical coating(s); that operates onthe slow axis of the emitted laser diode light and the TE-mode ofindividual reflection optical coating(s) fabricated by optical bondingor other low-loss method into a single piece of material; that operateson the fast axis of the emitted laser diode light and the TE-mode ofindividual reflection optical coating(s) fabricated by optical bondingor other low-loss method into a single piece of material; that operateson the slow axis of the emitted laser diode light and the TM-mode ofindividual reflection optical coating(s) fabricated by optical bondingor other low-loss method into a single piece of material; and thatoperates on the fast axis of the emitted laser diode light and theTM-mode of individual reflection optical coating (s) fabricated byoptical bonding or other low-loss method into a single piece ofmaterial.

Moreover there is provided a laser source comprising of the following:one or more volume Bragg gratings followed by one or more optical; theoutput light direction from the optical coating(s) is 90° with respectto the output light direction from the volume Bragg grating(s) and anoutput coupler to complete the optical cavity and define the operatingwavelength of each laser diode source; the brightness of the sum of theindividual laser diode beams after being combined by the volume Bragggratings(s), the optical coating(s) and the output coupler is N timesbrighter than that of an individual laser diode beam, with N is thenumber of individual laser diode beams, C is the number of opticalcoating(s), and N/C is the number of individual laser diode beams beingcombined by the volume Bragg grating(s) as groups; the opticalbandwidths of each individual combination of laser diodes combined bythe volume Bragg grating(s) are mutually exclusive; given an arbitrarycentral blue wavelength λ_(c), the optical bandwidth from volume Bragggrating M=Δλ_(M), the optical bandwidth of volume Bragg gratingM-1=Δλ_(M-1) such that Δλ_(M-1)≈Δλ_(M) andλ_(c)(Δλ_(M))−λ_(c)(Δλ_(M-1))≥Δλ_(M-1), the optical bandwidth fromvolume Bragg grating M-2=Δλ_(M-2), such that Δλ_(M-2)≈Δλ_(M) andλ_(c)(Δλ_(M-1))−λ_(c)(Δλ_(M-2))≥Δλ_(M-2), and so on; giving an arbitrarycentral blue wavelength λ_(c), the optical bandwidth from opticalcoating X=Δλ_(X), the optical bandwidth of optical coating X-1=Δλ_(X-1)such that Δλ_(X-1)≈λ_(X) and λ_(c)(Δλ_(X))−λ_(c)(Δλ_(X-1))≥Δλ_(X-1), theoptical bandwidth from optical coating X-2=λ_(X-2), such thatλ_(X-2)≈Δλ_(X) and λ_(c)(Δλ_(X-1))−λ_(c)(λ_(X-2))≥Δλ_(X-2), and so on;giving an arbitrary central blue wavelength λ_(c), the optical bandwidthfrom optical coating X=Δλ_(X) and the optical bandwidth of the sum ofvolume Bragg grating(s) ΣΔλ_(M1) such that Δλ_(X)≥ΣΔλ_(M1) andλ_(c)(Δλ_(X))≈λ_(c)(ΣΔλ_(M1)), the optical bandwidth from opticalcoating X-1=Δλ_(X-1) and the optical bandwidth of the sum of volumeBragg grating(s) ΣΔλ_(M2) such that Δλ_(X-1)≥Δλ_(M2) andλ_(c)(Δλ_(X-1))≈λ_(c)(ΣΔλ_(M2)), and so on.

Further there is provided these high power lasers, systems and methodshaving one or more of the following features: that utilizes thereflection volume Bragg grating(s) operating in the laser diode slowaxis and TE-mode of the reflection volume Bragg grating(s), followed byoptical coating(s) operating in the laser diode fast axis and TE-mode ofthe optical coating(s); that utilizes the reflection volume Bragggrating(s) operating in the laser diode fast axis and TE-mode of thereflection volume Bragg grating(s), followed by optical coating(s)operating in the laser diode slow axis and TE-mode of the opticalcoating(s); that utilizes the reflection volume Bragg grating(s)operating in the laser diode slow axis and TE-mode of the reflectionvolume Bragg grating(s), followed by optical coating(s) operating in thelaser diode fast axis and TM-mode of the optical coating(s); thatutilizes the reflection volume Bragg grating(s) operating in the laserdiode fast axis and TE-mode of the reflection volume Bragg grating(s),followed by optical coating(s) operating in the laser diode slow axisand TM-mode of the optical coating(s); that utilizes the reflectionvolume Bragg grating(s) operating in the laser diode slow axis andTM-mode of the reflection volume Bragg grating(s), followed by opticalcoating(s) operating in the laser diode fast axis and TE-mode of theoptical coating(s); that utilizes the reflection volume Bragg grating(s)operating in the laser diode fast axis and TM-mode of the reflectionvolume Bragg grating(s), followed by optical coating(s) operating in thelaser diode slow axis and TE-mode of the optical coating(s); thatutilizes the reflection volume Bragg grating(s) operating in the laserdiode slow axis and TM-mode of the reflection volume Bragg grating(s),followed by optical coating(s) operating in the laser diode fast axisand TM-mode of the optical coating(s); that utilizes the reflectionvolume Bragg grating(s) operating in the laser diode fast axis andTM-mode of the reflection volume Bragg grating(s), followed by opticalcoating(s) operating in the laser diode slow axis and TM-mode of theoptical coating(s); that utilizes the transmission volume Bragggrating(s) operating in the laser diode slow axis and TE-mode of thetransmission volume Bragg grating(s), followed by optical coating(s)operating in the laser diode fast axis and TE-mode of the opticalcoating(s); that utilizes the transmission volume Bragg grating(s)operating in the laser diode fast axis and TE-mode of the transmissionvolume Bragg grating(s), followed by optical coating(s) operating in thelaser diode slow axis and TE-mode of the optical coating(s); thatutilizes the transmission volume Bragg grating(s) operating in the laserdiode slow axis and TE-mode of the transmission volume Bragg grating(s),followed by optical coating(s) operating in the laser diode fast axisand TM-mode of the optical coating(s); that utilizes the transmissionvolume Bragg grating(s) operating in the laser diode fast axis andTE-mode of the transmission volume Bragg grating(s), followed by opticalcoating(s) operating in the laser diode slow axis and TM-mode of theoptical coating(s); that utilizes the transmission volume Bragggrating(s) operating in the laser diode slow axis and TM-mode of thetransmission volume Bragg grating(s), followed by optical coating(s)operating in the laser diode fast axis and TE-mode of the opticalcoating(s); that utilizes the transmission volume Bragg grating(s)operating in the laser diode fast axis and TM-mode of the transmissionvolume Bragg grating(s), followed by optical coating(s) operating in thelaser diode slow axis and TE-mode of the optical coating(s); thatutilizes the transmission volume Bragg grating(s) operating in the laserdiode slow axis and TM-mode of the transmission volume Bragg grating(s),followed by optical coating(s) operating in the laser diode fast axisand TM-mode of the optical coating(s); and that utilizes thetransmission volume Bragg grating(s) operating in the laser diode fastaxis and TM-mode of the transmission volume Bragg grating(s), followedby optical coating(s) operating in the laser diode slow axis and TM-modeof the optical coating(s) in combination with an output coupler whichdefines the wavelength of each source and the co-linear propagation ofeach laser beam.

Yet further there is provided a laser source comprising of thefollowing: one or more optical coatings followed by one or more volumeBragg gratings; the output light direction from the volume Bragggrating(s) is 90° with respect to the output light direction from theoptical coating(s) as defined by the optical cavity completed by theoutput coupler; the brightness of the sum of the individual laser diodebeams after being combined by the volume Bragg gratings(s) and theoptical coating(s) is N times brighter than that of an individual laserdiode beam, where N is the number of individual laser diode beams, B isthe number of volume Bragg grating(s), and N/B is the number ofindividual laser diode beams being combined by the optical coating(s) asgroups; the optical bandwidths of each individual combination of laserdiodes combined by the volume Bragg grating(s) are mutually exclusive;the optical bandwidths of each individual combination of laser diodescombined by optical coating(s) are mutually exclusive; given anarbitrary central blue wavelength λ_(c), the optical bandwidth fromvolume Bragg grating M=Δλ_(M), the optical bandwidth of volume Bragggrating M-1=Δλ_(M-1) such that Δλ_(M-1)≈Δλ_(M) andλ_(c)(Δλ_(M))−λ_(c)(Δλ_(M-1))≥Δλ_(M-1), the optical bandwidth fromvolume Bragg grating M-2=Δλ_(M-2), such that Δλ_(M-2)≈Δλ_(M) andλ_(c)(Δλ_(M-1))−λ_(c)(Δλ_(M-2))≥Δλ_(M-2), and so on; given an arbitrarycentral blue wavelength λ_(c), the optical bandwidth from opticalcoating X=Δλ_(X), the optical bandwidth of optical coating X-1=Δλ_(X-1)such that Δλ_(X-1)≈Δλ_(X) and λ_(c)(Δλ_(X))−λ_(c)(Δλ_(X-1))≥Δλ_(X-1),the optical bandwidth from optical coating X-2=Δλ_(X-2), such thatΔλ_(X-2)≈Δλ_(X) and λ_(c)(Δλ_(X-1))−λ_(c)(Δλ_(X-2))≥Δλ_(X-2), and so on;given an arbitrary central blue wavelength λ_(c), the optical bandwidthfrom volume Bragg grating X=Δλ_(X) and the optical bandwidth of the sumof coatings(s) ΣΔλ_(M1) such that Δλ_(X)≥Δλ_(M1) andλ_(c)(Δλ_(X))≈λ_(c)(ΣΔλ_(M1)), the optical bandwidth from volume Bragggrating X-1=Δλ_(X-1) and the optical bandwidth of the sum of opticalcoating(s) Δλ_(M2) such that Δλ_(X-1)≥ΣΔλ_(M2) andλ_(c)(ΣΔλ_(X-1))≈λ_(c)(ΣΔλ_(M2)), and so on.

Further there is provide a laser source comprising of the following: oneor more volume Bragg grating(s) followed by one or more volume Bragggrating(s); the output light direction from the following volume Bragggrating(s) is 90° with respect to the output light direction from theprevious volume Bragg grating(s) as defined by the optical cavitycompleted by the output coupler; the brightness of the sum of theindividual laser diode beams after being combined by the volume Bragggratings(s) is N times brighter than that of an individual laser diodebeam, with N is the number of individual laser diode beams, B is thenumber of secondary volume Bragg grating(s), and N/B is the number ofindividual laser diode beams being combined by the primary volume Bragggrating(s) as groups; the optical bandwidths of each individualcombination of laser diodes combined by the primary volume Bragggrating(s) are mutually exclusive; the optical bandwidths of eachindividual combination of laser diodes combined by the secondary volumeBragg grating(s) are mutually exclusive; given an arbitrary central bluewavelength λ_(c), the optical bandwidth from the primary volume Bragggrating M=Δλ_(M), the optical bandwidth of the primary volume Bragggrating M-1=Δλ_(M-1) such that Δλ_(M-1)≈Δλ_(M) andλ_(c)(Δλ_(M))−λ_(c)(Δλ_(M-1))≥Δλ_(M-1), the optical bandwidth from theprimary volume Bragg grating M-2=Δλ_(M-2), such that Δλ_(M-2)≈Δλ_(M) andλ_(c)(Δλ_(M-1))−λ_(c)(Δλ_(M-2))≥Δλ_(M-2), and so on; given an arbitrarycentral blue wavelength λ_(c), the optical bandwidth from the secondaryvolume Bragg grating X=Δλ_(X), the optical bandwidth of secondary volumeBragg grating X-1=Δλ_(X-1) such that Δλ_(X-1)≈Δλ_(X) andλ_(c)(Δλ_(X))−λ_(c)(Δλ_(X-1))≥Δλ_(X-1), the optical bandwidth fromsecondary volume Bragg grating X-2=Δλ_(X-2), such that Δλ_(X-2)≈Δλ_(X)and λ_(c)(Δλ_(X-1))−λ_(c)(Δλ_(X-2))≥Δλ_(X-2), and so on; given anarbitrary central blue wavelength λ_(c), the optical bandwidth from thesecondary volume Bragg grating X=Δλ_(X) and the optical bandwidth of thesum of the primary volume Bragg gratings ΣΔλ_(M1) such thatΔλ_(X)≥ΣΔλ_(M1) and λ_(c)(Δλ_(X))≈λ_(c)(ΣΔλ_(M1)), the optical bandwidthfrom the secondary volume Bragg grating X-1=Δλ_(X-1) and the opticalbandwidth of the sum of the primary volume Bragg gratings ΣΔλ_(M2) suchthat Δλ_(X-1)≥ΣΔλ_(M2) and λ_(c)(Δλ_(X-1))≈λ_(c)(ΣΔλ_(M2)), and so on.

Moreover, there is provided a laser source or method having one or moreof the following features: that utilizes the primary reflection volumeBragg grating(s) operating in the laser diode slow axis and TE-mode ofthe primary reflection volume Bragg grating(s), followed by secondaryreflection volume Bragg grating(s) operating in the laser diode fastaxis and TE-mode of the secondary reflection volume Bragg grating(s);that utilizes the primary reflection volume Bragg grating(s) operatingin the laser diode fast axis and TE-mode of the optical coating(s),followed by reflection volume Bragg grating(s) operating in the laserdiode slow axis and TE-mode of the reflection volume Bragg grating(s);that utilizes the primary reflection volume Bragg grating(s) operatingin the laser diode slow axis and TE-mode of the optical coating(s),followed by secondary reflection volume Bragg grating(s) operating inthe laser diode fast axis and TM-mode of the secondary reflection volumeBragg grating(s); that utilizes the primary reflection volume Bragggrating(s) operating in the laser diode fast axis and TE-mode of theoptical coating(s), followed by secondary reflection volume Bragggrating(s) operating in the laser diode slow axis and TM-mode of thesecondary reflection volume Bragg grating(s); that utilizes the primaryreflection volume Bragg grating(s) operating in the laser diode slowaxis and TM-mode of the optical coating(s), followed by secondaryreflection volume Bragg grating(s) operating in the laser diode fastaxis and TE-mode of the secondary reflection volume Bragg grating(s);that utilizes the primary reflection volume Bragg grating(s) operatingin the laser diode fast axis and TM-mode of the optical coating(s),followed by secondary reflection volume Bragg grating(s) operating inthe laser diode slow axis and TE-mode of the secondary reflection volumeBragg grating(s); that utilizes the primary reflection volume Bragggrating(s) operating in the laser diode slow axis and TM-mode of theoptical coating(s), followed by secondary reflection volume Bragggrating(s) operating in the laser diode fast axis and TM-mode of thesecondary reflection volume Bragg grating(s); that utilizes the primaryreflection volume Bragg grating(s) operating in the laser diode fastaxis and TM-mode of the optical coating(s), followed by secondaryreflection volume Bragg grating(s) operating in the laser diode slowaxis and TM-mode of the secondary reflection volume Bragg grating(s);that utilizes the primary reflection volume Bragg grating(s) operatingin the laser diode slow axis and TE-mode of the primary reflectionvolume Bragg grating(s), followed by secondary transmission volume Bragggrating(s) operating in the laser diode fast axis and TE-mode of thesecondary transmission volume Bragg grating(s); that utilizes theprimary reflection volume Bragg grating(s) operating in the laser diodefast axis and TE-mode of the primary reflection volume Bragg grating(s),followed by secondary transmission volume Bragg grating(s) operating inthe laser diode slow axis and TE-mode of the secondary transmissionvolume Bragg grating(s); that utilizes the primary reflection volumeBragg grating(s) operating in the laser diode slow axis and TE-mode ofthe primary reflection volume Bragg grating(s), followed by secondarytransmission volume Bragg grating(s) operating in the laser diode fastaxis and TM-mode of the secondary transmission volume Bragg grating(s);that utilizes the primary reflection volume Bragg grating(s) operatingin the laser diode fast axis and TE-mode of the primary reflectionvolume Bragg grating(s), followed by secondary transmission volume Bragggrating(s) operating in the laser diode slow axis and TM-mode of thesecondary transmission volume Bragg grating(s); that utilizes theprimary reflection volume Bragg grating(s) operating in the laser diodeslow axis and TM-mode of the primary reflection volume Bragg grating(s),followed by secondary transmission volume Bragg grating(s) operating inthe laser diode fast axis and TE-mode of the secondary transmissionvolume Bragg grating(s); that utilizes the primary reflection volumeBragg grating(s) operating in the laser diode fast axis and TM-mode ofthe primary reflection volume Bragg grating(s), followed by secondarytransmission volume Bragg grating(s) operating in the laser diode slowaxis and TE-mode of the secondary transmission volume Bragg grating(s);that utilizes the primary reflection volume Bragg grating(s) operatingin the laser diode slow axis and TM-mode of the primary reflectionvolume Bragg grating(s), followed by secondary transmission volume Bragggrating(s) operating in the laser diode fast axis and TM-mode of thesecondary transmission volume Bragg grating(s); that utilizes theprimary reflection volume Bragg grating(s) operating in the laser diodefast axis and TM-mode of the primary reflection volume Bragg grating(s),followed by secondary transmission volume Bragg grating(s) operating inthe laser diode slow axis and TM-mode of the secondary transmissionvolume Bragg grating(s); that utilizes the primary transmission volumeBragg grating(s) operating in the laser diode slow axis and TE-mode ofthe primary transmission volume Bragg grating(s), followed by secondaryreflection volume Bragg grating(s) operating in the laser diode fastaxis and TE-mode of the secondary reflection volume Bragg grating(s);that utilizes the primary transmission volume Bragg grating(s) operatingin the laser diode fast axis and TE-mode of the primary transmissionvolume Bragg grating(s), followed by secondary reflection volume Bragggrating(s) operating in the laser diode slow axis and TE-mode of thesecondary reflection volume Bragg grating(s); that utilizes the primarytransmission volume Bragg grating(s) operating in the laser diode slowaxis and TE-mode of the primary transmission volume Bragg grating(s),followed by secondary reflection volume Bragg grating(s) operating inthe laser diode fast axis and TM-mode of the secondary reflection volumeBragg grating(s); that utilizes the primary transmission volume Bragggrating(s) operating in the laser diode fast axis and TE-mode of theprimary transmission volume Bragg grating(s), followed by secondaryreflection volume Bragg grating(s) operating in the laser diode slowaxis and TM-mode of the secondary reflection volume Bragg grating(s);that utilizes the primary transmission volume Bragg grating(s) operatingin the laser diode slow axis and TM-mode of the primary transmissionvolume Bragg grating(s), followed by secondary reflection volume Bragggrating(s) operating in the laser diode fast axis and TE-mode of thesecondary reflection volume Bragg grating(s); that utilizes the primarytransmission volume Bragg grating(s) operating in the laser diode fastaxis and TM-mode of the primary transmission volume Bragg grating(s),followed by secondary reflection volume Bragg grating(s) operating inthe laser diode slow axis and TE-mode of the secondary reflection volumeBragg grating(s); that utilizes the primary transmission volume Bragggrating(s) operating in the laser diode slow axis and TM-mode of theprimary transmission volume Bragg grating(s), followed by secondaryreflection volume Bragg grating(s) operating in the laser diode fastaxis and TM-mode of the secondary reflection volume Bragg grating(s);that utilizes the primary transmission volume Bragg grating(s) operatingin the laser diode fast axis and TM-mode of the primary transmissionvolume Bragg grating(s), followed by secondary reflection volume Bragggrating(s) operating in the laser diode slow axis and TM-mode of thesecondary reflection volume Bragg grating(s); that utilizes the primarytransmission volume Bragg grating(s) operating in the laser diode slowaxis and TE-mode of the primary transmission volume Bragg grating(s),followed by secondary transmission volume Bragg grating(s) operating inthe laser diode fast axis and TE-mode of the secondary transmissionvolume Bragg grating(s); that utilizes the primary transmission volumeBragg grating(s) operating in the laser diode fast axis and TE-mode ofthe primary transmission volume Bragg grating(s), followed by secondarytransmission volume Bragg grating(s) operating in the laser diode slowaxis and TE-mode of the secondary transmission volume Bragg grating(s);that utilizes the primary transmission volume Bragg grating(s) operatingin the laser diode slow axis and TE-mode of the primary transmissionvolume Bragg grating(s), followed by secondary transmission volume Bragggrating(s) operating in the laser diode fast axis and TM-mode of thesecondary transmission volume Bragg grating(s); that utilizes theprimary transmission volume Bragg grating(s) operating in the laserdiode fast axis and TE-mode of the primary transmission volume Bragggrating(s), followed by secondary transmission volume Bragg grating(s)operating in the laser diode slow axis and TM-mode of the secondarytransmission volume Bragg grating(s); that utilizes the primarytransmission volume Bragg grating(s) operating in the laser diode slowaxis and TM-mode of the primary transmission volume Bragg grating(s),followed by secondary transmission volume Bragg grating(s) operating inthe laser diode fast axis and TE-mode of the secondary transmissionvolume Bragg grating(s); that utilizes the primary transmission volumeBragg grating(s) operating in the laser diode fast axis and TM-mode ofthe primary transmission volume Bragg grating(s), followed by secondarytransmission volume Bragg grating(s) operating in the laser diode slowaxis and TE-mode of the secondary transmission volume Bragg grating(s);that utilizes the primary transmission volume Bragg grating(s) operatingin the laser diode slow axis and TM-mode of the primary transmissionvolume Bragg grating(s), followed by secondary transmission volume Bragggrating(s) operating in the laser diode fast axis and TM-mode of thesecondary transmission volume Bragg grating(s); and, that utilizes theprimary transmission volume Bragg grating(s) operating in the laserdiode fast axis and TM-mode of the primary transmission volume Bragggrating(s), followed by secondary transmission volume Bragg grating(s)operating in the laser diode slow axis and TM-mode of the secondarytransmission volume Bragg grating(s) with the final element being aoutput coupler which defines the optical cavity through each of theBragg gratings to define the wavelength of each laser source from thefeedback from the output coupler.

Moreover there is provided a laser source comprising of the following:one or more optical coatings(s) as described in claim 30 followed by oneor more optical coating(s) as described in claim 30; the output lightdirection from the following optical coating(s) is 90° with respect tothe output light direction from the previous optical coating(s) and anoutput coupler to complete the optical cavity and provide the roundtripoptical path to define the wavelength of each laser diode source; thebrightness is now the sum of the individual laser diode beams afterbeing combined by the optical coating(s) N times brighter than that ofan individual laser diode beam, with N is the number of individual laserdiode beams, C is the number of secondary optical coating(s), and N/C isthe number of individual laser diode beams being combined by the primaryoptical coatings(s) as groups; the optical bandwidths of each individualcombination of laser diodes combined by the primary optical coatings(s)are mutually exclusive; the optical bandwidths of each individualcombination of laser diodes combined by the secondary optical coating(s)are mutually exclusive; given an arbitrary central blue wavelengthλ_(c), the optical bandwidth from the primary optical coating M=Δλ_(M),the optical bandwidth of the primary optical coating M-1=Δλ_(M-1) suchthat Δλ_(M-1)≈Δλ_(M) and λ_(c)(Δλ_(M))−λ_(c)(Δλ_(M-1))≥Δλ_(M-1), theoptical bandwidth from the primary optical coating M-2≈Δλ_(M-2), suchthat Δλ_(M-2)=Δλ_(M) and λ_(c)(λ_(M-1))−λ_(c)(Δλ_(M-2))≥Δλ_(M-2), and soon; given an arbitrary central blue wavelength λ_(c), the opticalbandwidth from the secondary optical coating X=Δλ_(X), the opticalbandwidth of secondary optical coating X-1=Δλ_(X-1) such thatΔλ_(X-1)≈Δλ_(X) and λ_(c)(Δλ_(X))−λ_(c)(Δλ_(X-1))≥Δλ_(X-1), the opticalbandwidth from secondary optical coating X-2=Δλ_(X2), such thatΔλ_(X-2)≈Δλ_(X) and λ_(c)(Δλ_(X-1))−λ_(c)(Δλ_(X-2))≥Δλ_(X-2), and so on;given an arbitrary central blue wavelength λ_(c), the optical bandwidthfrom the secondary coating X=Δλ_(X) and the optical bandwidth of the sumof the primary optical coatings ΣΔλ_(M1) such that Δλ_(X)≥ΣΔλ_(M1) andλ_(c)(Δλ_(X))≈λ_(c)(ΣΔλ_(M1)), the optical bandwidth from the secondaryoptical coating X-1=Δλ_(X-1) and the optical bandwidth of the sum of theprimary optical coatings ΣΔλ_(M2) such that Δλ_(X-1)≥ΣΔλ_(M2) andλ_(c)(Δλ_(X-1))≈λ_(c)(ΣΔλ_(M2)), and so on.

Further there is provided these high power lasers, systems and methodshaving one or more of the following features: that utilizes the primaryoptical coating(s) operating in the laser diode slow axis and TE-mode ofthe primary optical coating(s), followed by secondary optical coating(s)operating in the laser diode fast axis and TE-mode of the secondaryoptical coating(s); that utilizes the primary optical coating(s)operating in the laser diode fast axis and TE-mode of the opticalcoating(s), followed by secondary optical coating(s) operating in thelaser diode slow axis and TE-mode of the secondary optical coating(s);that utilizes the primary optical coating(s) operating in the laserdiode slow axis and TE-mode of the optical coating(s), followedsecondary optical coating(s) operating in the laser diode fast axis andTM-mode of the secondary optical coating(s); that utilizes the primaryoptical coating(s) operating in the laser diode fast axis and TE-mode ofthe optical coating(s), followed by secondary optical coating(s)operating in the laser diode slow axis and TM-mode of the secondaryoptical coating(s); that utilizes the primary optical coating(s)operating in the laser diode slow axis and TM-mode of the opticalcoating(s), followed by secondary optical coating(s) operating in thelaser diode fast axis and TE-mode of the secondary optical coating(s);that utilizes the primary optical coating(s) operating in the laserdiode fast axis and TM-mode of the optical coating(s), followed bysecondary optical coating(s) operating in the laser diode slow axis andTE-mode of the secondary optical coating(s); that utilizes the primaryoptical coating(s) operating in the laser diode slow axis and TM-mode ofthe optical coating(s), followed by secondary optical coating(s)operating in the laser diode fast axis and TM-mode of the secondaryoptical coating(s); that utilizes the primary optical coating(s)operating in the laser diode fast axis and TM-mode of the opticalcoating(s), followed by secondary optical coating(s) operating in thelaser diode slow axis and TM-mode of the secondary optical coating(s)with an output coupler at the exit of the system providing the opticalfeedback to each of the laser diode sources through the filter systemdescribed; operating in the 400-500 nm range with an output power of >1Watt and a beam parameter product of 5 mm-mrad and larger; operating inthe 500-600 nm range with an output power of >1 Watt and a beamparameter product of 5 mm-mrad and larger; operating in the 720-800 nmrange with an output power of >1 Watt and a beam parameter product of 5mm-mrad and larger; and, operating in the 800-900 nm range with anoutput power of >1 Watt and a beam parameter product of 5 mm-mrad andlarger.

Moreover, there is provided a high power, high brightness laser system,having: a plurality of laser diodes, each having a power of not lessthan 0.25 W, wherein each of the plurality of laser diodes is configuredto provide a laser beam along a laser beam path; a common externalcavity shared by each of the plurality of laser diodes; a collimatingoptic in the laser beam paths for creating parallel beams from each ofthe plurality of laser diodes; a beam combination optic in the commonexternal cavity and in the laser beam paths; wherein the beamcombination optic determines the wavelength of each laser diode andaligns each laser beam path from the plurality of laser diodes to beco-linear and overlapping in space, whereby a composite output laserbeam is provided; and, the spatial brightness of the composite outputlaser beam is n times the brightness of any single laser diode in theplurality of laser diodes, where brightness is defined as the combinedpower divided by the aperture-divergence product.

Still further there is provided these laser systems and methods havingone or more of the following features: wherein the beam combinationoptic is a set of optical filters that are used at the edge of eitherthe low pass or high pass end of the spectrum for a bandpass filter;operating in the 400-500 nm range with an output power of not less than100 Watts and a beam parameter product of 0.1 mm-mrad and larger;operating in the 500-600 nm range with an output power of not less than100 Watts and a beam parameter product of 0.1 mm-mrad and larger;operating in the 720-800 nm range with an output power not less than 100Watts and a beam parameter product of 0.1 mm-mrad and larger; operatingin the 800-900 nm range with an output power of not less than 100 Wattsand a beam parameter product of 0.1 mm-mrad and larger; operating in the900-1200 nm range with an output power of not less than 100 Watts and abeam parameter product of 0.1 mm-mrad and larger; operating in the 1200nm-1120 nm range with an output power of not less than 100 Watts and abeam parameter product of 0.1 mm-mrad and larger; operating in the1400-1500 nm range with an output power of not less than 100 Watts and abeam parameter product of 0.1 mm-mrad and larger; operating in the1500-2200 nm range with an output power of not less than 100 Watts and abeam parameter product of 0.1 mm-mrad and larger; wherein the pluralityof laser diodes are inter-band cascade lasers; and where in the systemis operating in the 2200-3000 nm range with an output power of not lessthan 100 Watts and a beam parameter product of 0.1 mm-mrad and larger;wherein the beam combination optic comprises a plurality of volume Bragggrating filters; wherein a first volume Bragg gratings is configured toredirect a portion of the optical spectrum of a first laser beam from afirst laser diode in the plurality of laser diodes to be collinear withthe laser beam from a second laser diode in the plurality of laserdiodes; and, wherein the plurality of laser diodes are quantum cascadelasers and the system is operating in the 3000 nm-12000 nm range with anoutput power of not less than 100 Watts and a beam parameter product of0.1 mm-mrad and larger;

Additionally, there is provided these laser systems and methods havingone or more of the following features: wherein n is not less than 25;wherein the beam combination optic comprises a plurality of volume Bragggrating filters; wherein a first volume Bragg gratings is configured toredirect a portion of the optical spectrum of a first laser beam from afirst laser diode in the plurality of laser diodes to be collinear withthe a laser beam from a second laser diode in the plurality of laserdiodes; and wherein n is not less than 25; wherein the plurality oflaser diodes consists of N diodes; wherein each of the N diodes definesa 1^(st) peak of a lasing spectra; wherein the beam combining opticconsists of a plurality of volume Bragg grating consisting of N-1 volumeBragg grating filters and an output coupler; the volume Bragg gratingsand N-1 of the laser diodes configured in an optical association suchthat points of maximum transmission through each volume Bragg grating ofthe plurality of volume Bragg gratings coincide with the N-1, N-2 toN-(N-1) 1^(st) peak of N-1 laser diodes in the plurality of laserdiodes; whereby the N is equal to n; wherein N-1 is equal to n; andwherein laser diode N′ is not optically associated with a volume Bragggrating and the system provides the maximum beam deflection of laserdiode N′.

Yet additionally there is provided a high power, high brightness lasersystem having: a plurality of N laser diodes, wherein each of theplurality of laser diodes is configured to provide a laser beam along alaser beam path at a laser beam power; wherein the laser beam pathcomprises an output propagation direction; a common external cavityshared by each of the plurality of laser diodes; a collimating optic inthe output propagation direction laser beam paths for creating parallelbeams from each of the plurality of laser diodes; a beam combinationoptic in the common external cavity and in the output propagationdirection laser beam paths; wherein the beam combining optic comprisesN-1 optical elements having optical coatings, whereby the opticalelements redirect a portion of the optical spectrum of the laser beamfrom a laser diode in the plurality of laser diodes at an angle up to90° with respect to the output propagation direction laser beam paths,thereby providing a composite output laser beam defining a brightness;and, whereby the brightness of the composite output laser beam is ntimes the brightness of any single laser diode in the plurality of laserdiodes, where brightness is defined as the combined power divided by theaperture-divergence product.

Still further there is provided these laser systems and methods havingone or more of the following features: wherein N=n; wherein N-1=n.

Still further there is provided these laser systems and methods havingone or more of the following features: operating in the 400-500 nm rangewith an output power of not less than 10 W and a beam parameter productof 0.1 mm-mrad and larger; operating in the 500-600 nm range with anoutput power of not less than 10 W and a beam parameter product of 0.1mm-mrad and larger; wherein the laser beam power is not less than 0.5 W;and, wherein the laser beam power is not less than 1 W.

In addition there is provided a high power, high brightness laser systemhaving: a plurality of N laser diodes, wherein each of the plurality oflaser diodes is configured to provide a laser beam along a laser beampath at a laser beam power; wherein the laser beam path comprises anoutput propagation direction; a common external cavity shared by each ofthe plurality of laser diodes; a collimating optic in the outputpropagation direction laser beam paths for creating parallel beams fromeach of the plurality of laser diodes; a beam combination optic in thecommon external cavity and in the output propagation direction laserbeam paths; wherein the beam combining optic comprises N-1 opticalelements; wherein the optical elements consist of volume Bragg gratingsand optical coatings elements, wherein the volume Bragg gratings and theoptical coating elements follow each other along the laser beam paths;wherein an output light direction from the optical coating is 90° withrespect to the output light direction from the volume Bragg grating,thereby providing a combined output laser beam defining a brightness;and, the brightness of the sum of the individual laser diode beams afterbeing combined by the volume Bragg gratings and the optical coatings isn times brighter than that of an individual laser diode beam; whereinn=N or n=N-1, N is the number of individual laser diode beams, C is thenumber of optical coatings, and N/C is the number of individual laserdiode beams being combined by the volume Bragg gratings and the outputcoupler.

Still further there is provided a high power, high brightness lasersystem having: a plurality of N laser diodes, wherein each of theplurality of laser diodes is configured to provide a laser beam along alaser beam path at a laser beam power; wherein the laser beam pathcomprises an output propagation direction; a common external cavityshared by each of the plurality of laser diodes; a collimating optic inthe output propagation direction laser beam paths for creating parallelbeams from each of the plurality of laser diodes; a beam combinationoptic in the common external cavity and in the output propagationdirection laser beam paths; wherein the beam combining optic comprisesN-1 optical elements; wherein the optical elements consist of volumeBragg gratings and optical coatings elements, wherein the volume Bragggratings and the optical coating elements follow each other along thelaser beam paths; wherein an output light direction from the volumeBragg grating is 90° with respect to the output light direction from theoptical coating element, thereby providing a combined output laser beamdefining a brightness; and, the brightness of the sum of the individuallaser diode beams after being combined by the volume Bragg gratings andthe optical coatings is n times brighter than that of an individuallaser diode beam; wherein n=N or n=N-1, N is the number of individuallaser diode beams, B is the number of volume Bragg gratings, and N/B isthe number of individual laser diode beams being combined by the opticalcoatings as groups.

Additionally, there is provided these laser systems and methods havingone or more of the following features: wherein, the optical bandwidthsof each individual combination of laser diodes combined by the volumeBragg grating(s) and output coupler in an external cavity are mutuallyexclusive; wherein, given an arbitrary central blue wavelength λ_(c),the optical bandwidth from volume Bragg grating M=Δλ_(M), the opticalbandwidth of volume Bragg grating M-1=Δλ_(M-1) such that Δλ_(M-1)≈Δλ_(M)and λ_(c)(Δλ_(M))−λ_(c)(Δλ_(M-1))≥Δλ_(M-1), the optical bandwidth fromvolume Bragg grating M-2=Δλ_(M-2), such that Δλ_(M-2)≈Δλ_(M) andλ_(c)(Δλ_(M-1))−λ_(c)(Δλ_(M-2))≥Δλ_(M-2), and so on; wherein given anarbitrary central blue wavelength λ_(c), the optical bandwidth fromoptical coating X=Δλ_(X), the optical bandwidth of optical coatingX-1=Δλ_(X-1) such that Δλ_(X-1)≈Δλ_(X) andλ_(c)(Δλ_(X))−λ_(c)(Δλ_(X-1))≥Δλ_(X-1), the optical bandwidth fromoptical coating X-2=Δλ_(X-2), such that Δλ_(X-2)≈Δλ_(X) andλ_(c)(Δλ_(X-1))−λ_(c)(Δλ_(X-2))≈Δλ_(X-2), and so on; and, wherein givenan arbitrary central blue wavelength λ_(c), the optical bandwidth fromoptical coating X=Δλ_(X) and the optical bandwidth of the sum of volumeBragg grating(s) ΣΔλ_(M1) such that Δλ_(X)≥ΣΔλ_(M1) andλ_(c)(Δλ_(X))≈λ_(c)(ΣΔλ_(M1)), the optical bandwidth from opticalcoating X-1=Δλ_(X-1) and the optical bandwidth of the sum of volumeBragg grating(s) ΣΔλ_(M2) such that Δλ_(X-1)≥ΣΔλ_(M2) andλ_(c)(Δλ_(X-1))≈λ_(c)(ΣΔλ_(M2)), and so on

Moreover, there is provided a high power, high brightness laser systemhaving: a plurality of N laser diodes, wherein each of the plurality oflaser diodes is configured to provide a laser beam along a laser beampath at a laser beam power; wherein the laser beam path comprises anoutput propagation direction; a common external cavity shared by each ofthe plurality of laser diodes; a collimating optic in the outputpropagation direction laser beam paths for creating parallel beams fromeach of the plurality of laser diodes; a beam combination optic in thecommon external cavity and in the output propagation direction laserbeam paths; wherein the beam combining optic comprises N-1 opticalelements; wherein the optical elements comprises: a first means fordetermining the wavelength of a laser diode beam and directing the laserdiode beam path in an output path; a second means for determining thewavelength of a laser diode beam and directing the laser diode beam pathin an output path; wherein the output path for the first means is 90°with respect to the output path for the second means, thereby providinga combined output laser beam defining a brightness; and, the brightnessof the sum of the individual laser diode beams after being combined bythe first means and the second means is n times brighter than that of anindividual laser diode beam; wherein n=N or n=N-1, N is the number ofindividual laser diode beams, E′ is the number of first or the number ofsecond means, and N/E′ is the number of individual laser diode beamsbeing combined by the first means or the second means as groups.

Additionally, there is provided these laser systems and methods havingone or more of the following features: wherein the first means is aprimary volume Bragg grating; wherein the second means is a secondaryvolume Bragg grating; wherein the first means is a primary coating;wherein the second means is a secondary coating wherein the outputcoupler is a partially reflective element which may be an opticalcoating or a volume Bragg grating; wherein the system is in operating inthe 400-500 nm wavelength range; wherein the system is in operating inthe 500-600 nm wavelength range; wherein the system is in operating inthe 720-800 nm wavelength range; and wherein the system is in operatingin the 800-900 nm wavelength range.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 1A are schematics of an embodiment of an external cavitylaser system in accordance with the present inventions showing multiplelaser diodes combined by a feedback signal from an output couplerintegral to the combiner block, which forces each laser diode to operateat a specific wavelength.

FIG. 2 is a schematic of an embodiment of an external cavity lasersystem in accordance with the present inventions with the output couplerexternal to the combiner.

FIG. 3 is a schematic of an embodiment of an external cavity lasersystem in accordance with the present inventions, extended to lock uplaser diodes in a two dimensional array.

FIG. 4 is a graph showing the relationship between each of thetransmission functions of an embodiment of a bandpass filter used inaccordance with the present inventions.

FIG. 5 is the transmission function for an embodiment of a combinerblock showing the maximum transmission peaks for each of the laserdiodes which will have the lowest loss in the external cavity resultingin the passive locking of each laser diode to the appropriatetransmission peak when using the high wavelength side of the bandpasstransmission functions in accordance with the present inventions.

FIG. 6 is the transmission function for an embodiment of a combinerblock based when using the low wavelength side of the bandpasstransmission functions in accordance with the present inventions.

FIG. 7 is the transmission function for an embodiment of a laser diodebeam combiner block based on a beam divergence of 0.25 degrees from thelaser diodes using the high wavelength edge of the bandpass filtertransmission function in accordance with the present inventions.

FIG. 8 is transmission function for an embodiment of a combiner blockusing the lower wavelength edge of the bandpass filter transmissionfunction for diverging laser diode light in accordance with the presentinventions.

FIG. 9 is a graph showing the overlap of an embodiment of a combinerblock transmission function and the feedback from an embodiment of anexternal cavity bandpass transmission filter function in accordance withthe present inventions, which defines the oscillating bandwidth for thelaser diode array.

FIG. 10 is a graph showing the overlap of an embodiment of a combinerblock transmission function from one row and an embodiment of a combinerblock transmission function used in a second row that is the wider ofthe bandpass transmission functions allowing feedback to laser diodes intwo axes in accordance with the present inventions.

FIG. 11 is a graph showing the overlap of the response functions for anembodiment of a combiner block for the case of a broadband outputcoupler reflection function and how by using a narrowband output couplerreflection function the oscillating bandwidth can be reduced for oneaxis in accordance with the present inventions.

FIG. 12 is a graph showing an embodiment of a response function for theoverlap of the response functions for the combiner block for the case ofa broadband output coupler reflection functions and how by usingnarrowband output coupler reflection functions the oscillating bandwidthcan be reduced for a two-axis system, as shown in FIG. 3, and inaccordance with the present inventions.

FIG. 13 is a block schematic of an embodiment of a laser system inaccordance with the present inventions.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In general, the present inventions relate to methods, systems andapparatus for the spectral beam combining of laser beams to providehigher brightness laser beams. In particular, embodiments of the presentinventions relate to the combining of lower brightness laser beams, suchas the beams from laser diodes, into high brightness laser beams, whichare comparable to the laser beams obtained from fiber lasers.

Generally, an embodiment of the present invention is a high-power diodelaser system capable of high power and high brightness operation usingtwo or more individual laser diodes in a common external cavity. Thelaser can be used in various applications, such as materials processing,laser-assisted deposition manufacturing, and pumping of other laser gainmedium. The output from the common external cavity of the laserincreases the brightness by spectral beam combination in the fast axis,slow axis, or both axes simultaneously. This method of spectral beamcombining is more elegant and less complex than all other previous beamcombination methods envisioned for laser diode arrays.

Embodiments of the present inventions provide high brightness laserbeams having narrow spectral bandwidth. This narrow spectral bandwidthcan have advantages in pumping rare earth fiber lasers, rare earthlasers, Raman lasers and Raman fiber lasers.

Embodiments of the present inventions are useful in, for example,welding, cutting, surface cladding and 3-D printing, as well as for apump source for other laser systems, and other applications. Embodimentsof the present inventions provide laser beam brightness that are equalto and competitive with current fiber lasers, e.g., the laser beams ofthe present inventions having about 1 kW to about 10 kW, 2 kW to 8 kW,about 5 W to about 20 kW and all powers within these ranges, as well asgreater and lower powers, and for these powers having BPP (BeamParameter Products) of from about 1 mm mrad to about 40 mm mrad, about30 mm mrad to about 35 mm mrad, and all values within these ranges, aswell as greater and lower values. Embodiments of the present inventionsare a novel way for increasing the spatial brightness of a laser diodearray, and provide a high brightness laser beam from a highly compactsystem, e.g., having a maximum dimension, either length, width or crosssection of less than about 100 cm, less than about 5 cm, from about 5 cmto about 200 cm, all sizes within these ranges, and larger and smallersizes, and also, among other things, greatly simplify themanufacturability of a spectral beam combined laser diode array.

This invention applies to all wavelengths of laser diodes. Thus, to theextent that this specification focusses on embodiments and examples forproducing high power, high brightness laser sources in the visiblespectrum using the high power visible blue laser diodes, the applicationof the present inventions and their scope should not be so limited.

Embodiments of the present inventions answer the need for the ability tolaser process high reflectivity materials that are very difficult, ifnot impossible to process with IR lasers. Visible laser light,preferable green and blue laser light and more preferably blue laserlight is typically strongly absorbed by materials that are highlyreflective in the IR. Thus, blue laser light, with the increasedbrightness obtained through the present embodiments of spectral beamcombining systems is ideal for processing materials such as copper,gold, aluminum, copper to aluminum, copper to steel, gold to aluminum,gold to steel, copper to nickel copper powder, aluminum powder, copperallows, aluminum alloys, titanium alloys, nickel alloys, etc.

Embodiments of the present invention greatly simplifies the wavelengthbeam combination method by using dichroic filters or volume Bragggratings in an external cavity to combine the outputs of N-laser diodes,thus preferably eliminating the need for a separate wavelength controlelement on each laser diode. The laser diodes are first anti-reflection(AR) coated or low-reflection coated on the front facet making the laserdiode a gain element, which is ideal for integrating into an externalcavity. The High Reflectivity (HR) coating on the back facet of thelaser diodes is broadband (>20 nm) and generally does not need to bemodified. Each filter in the external cavity may be either a low pass,high pass or bandpass filter as long as the overlapping transmissionfunctions result in a separation of the passbands by a predeterminedamount. This filter is placed in the collimated output of N-lasers wherethe value of N is determined by the final bandwidth needed for the lasersource and the overlapping passbands of each filter which sets thechannel spacing.

In an embodiment using single mode diodes, the divergence could be 0.1mm-mrad. In embodiments the beam combining optic consists of the opticalfilters in an optical cavity where the round trip from the diode to theoutput coupler through the filter defines the oscillating wavelength ofeach diode element. In an embodiment, the bandpass filters areindividual elements with air between each filter. In an embodiment thebandpass filters are assembled into a monolithic optical elementassembled with, for example, either optical bonding or transparent glue.

Turning to FIG. 1 there is shown an external cavity beam combiningassembly 100. The assembly 100 has a laser diode source 101, e.g., anarray of laser diodes, a laser diode bar, or a collection of individualchips. The assembly has collimating optics 151, 152, 153, 154, 155(preferably providing laser beams collimated in the slow axis, the fastaxis or both). The laser diode source has individual laser diodes 101 a,101 b, 101 c, 101 d, 101 e. The laser diode source 101 provides laserbeams, 102 a, 102 b, 102 c, 102 d, 102 e, which travel along laser beampaths that are parallel. The laser beams have a direction ofpolarization as shown by arrow 107 (TE with respect to the diode laser,TM with respect to the coating). The laser diodes, e.g., 101 a, eachhave a surface or face, e.g., 103 a, having an AR (anti-reflection)coating or low-reflection coating. The laser diodes, e.g., 101 a, eachhave a surface or face, e.g., 104 a, having an HR (high-reflection)coating. The laser beams, e.g., 102 a, travel along their beam paths toan integral stack and optical coupler 105. The stack and optical coupler105 has TIR (total internal reflation) surface 112, such that the laserbeam 102 a is directed along the stack's length and combined with laserbeams 102 b, 102 b, 102 c, 102 d, and 102 e, which are directed by andfiltered by filters 108, 109, 110, 111, to provide laser beam 106. Theintegral stack may have the coatings immersed in the glass assembly, orthe may be individual glass parts with and air gap on one side of theoptical coating to enable a much steeper band edge, and optical coupler105, has a first transmission filter 108, a second transmission filter109, a third transmission filter 110, and a fourth transmission filter111. The first transmission filter 108 has a 446.25 nm Band Edge and a 6nm Bandpass, which is depicted by the transmission profile 108 a (foreach of these profiles the y-axis is % transmission and the x-axis iswavelength in nm). The second transmission filter 109 has a 447 nm BandEdge and a 6 nm Bandpass, which is depicted by transmission profile 109a. The third transmission filter 110 has a 447.75 nm Band Edge and a 6nm Bandpass, which is depicted by transmission profile 110 a. The fourthtransmission filter 111 has a 448.5 nm Band Edge and a 6 nm Bandpass,which is depicted by transmission profile 110 a.

In an embodiment the laser beams leaving the collimated laser diodedevice have a divergence of 4.5 mrad divergence in the slow axis. Thelaser beams can have divergent axis from about 0.1 mrad to about 5 mradfor this case because the laser beam divergence determines the steepnessof the filter band edge, the larger the divergence, the less sharp theband-edge and consequently the broader spacing required for each filter,and all divergences within this range, as well as larger and smallerdivergences.

In embodiments the external cavity beam combining assembly can have 1,2, 10, 20, a dozen, dozens, and hundreds of laser diodes, andcorresponding filters. The assembly can have 1, 2, 10, 20 or more laserdiode bars, and corresponding filters for each laser diode in the bar.Preferably, each diode laser is optically associated with (i.e., theyare on the laser beam path for that diode laser) its own filter; howeverin embodiments, 1, 2, 3 or more laser diodes can be optically associatedwith a single filter.

Turning to FIG. 1A there is shown an external cavity beam combiningassembly 200. The assembly 200 has a laser diode source 201, (preferablyproviding laser beams collimated in the slow axis, the fast axis orboth) e.g., an array of laser diodes, a laser diode bar, or a collectionof individual chips. The laser diode source has individual laser diodes201 a, 201 b, 201 c, 201 d, 201 e. The laser diode source 201 provideslaser beams, 202 a, 202 b, 202 c, 202 d, 202 e, which travel along laserbeam paths that are coincident with the laser beams. The laser beamshave a direction of polarization as shown by arrow 207. The laserdiodes, e.g., 201 a, each have a surface or face, e.g., 203 a, having anAR (anti-reflection) coating. The laser diodes, e.g., 201 a, each have asurface or face, e.g., 204 a, having an HR (high-reflection) coating.The laser beams, e.g., 202 a, travel along their beam paths to an stackof optical filters which may be integral or discrete with an air gap toone side and an optical coupler 205. The integral stack and opticalcoupler 205 has TIR (total internal reflation) surface, 212, such thatthe laser beam 202 a is directed along the length of the stack andcombined with laser beams 202 b, 202 b, 202 c, 202 d, and 202 e, whichare directed and filtered by VBG notch filters 208, 209, 210, 211, toprovide laser beam 206. The integral optical coupler 205, has a firstVBG notch filter 208, a second VBG notch filter 209, a third VBG notchfilter 210, a fourth VBG notch filter 211. The reflection spectrum onthe combined VGBs is shown by graph 213 (y-axis is % transmission andthe x-axis is wavelength in nm); showing the reflection spectrums forfirst VBG notch filter 208 a, the second VBG notch filter 209 a, thethird VBG notch filter 210 a, and the fourth VBG notch filter 211 a.VBGs enable the channel spacing to be substantially closer then withbandpass filter elements.

As used herein, the “external cavity” refers to the space or area thatis outside of, or away from the laser diode source, and in general isformed in, and includes, an optical block, optical blocks or opticalcomponents or similar type structures. For example, the external cavityis formed by an integral optical coupler, or the stack of filters andcoupler. The external cavity can be in, or encompass, an opticallytransmissive solid material, (e.g., silica, sapphire, etc.), free space(e.g., no solid material present), or both. The external cavity can bewithin, or defined by, a housing, which housing for example can make up,or contain, the laser assembly, a laser tool, or laser device. Thus, forexample, the housing can encompass some or all of the integral opticalcoupler, or it can encompass some or all of both the integral opticalcoupler and the laser diode source.

Thus, turning to FIG. 13 there is shown a block schematic diagram of anembodiment of a laser assembly 1300. The assembly 1300 has a diode array1301, that generates laser beams 1303, 1304, 1305, 1306, along laserbeam paths 1303 a, 1304 a, 1305 a, 1306 a respectively. The laser beamsare generated by diodes having collimating optics in optical associationwith the diodes 1370, 1371, 1372, 1373. The collimating optics may be asingle aspheric optic which is used to collimate the fast axis of thelaser diode sources, but leaves the slow axis slightly uncollimated, orthe collimating optic may consist of two optical elements, a fastacylindrical optic for collimating the fast axis of the laser diode anda slow acylindrical optic for collimating the slow axis of the laserdiode. The fast acylindrical optic is typically of a short focal lengthand mounted near or on the diode laser itself, while the slowacylindrical optic has a sufficiently long focal length to eithercircularize the divergence of the laser source or to meet the acceptanceangle requirements of the filters or VBGs used in the assembly. Thelaser beam paths extend from the diodes in the diode array 1301 to anoptical assembly 1320, which for example can be the optical blocks ofFIG. 3, the filter stack of FIG. 2, or the integral coupler of FIG. 1 or1A. The optical assembly 1320 combines the laser beams into laser beam1307 that travels along laser beam path 1307 a. There is an externalcavity 1302, which is external to the diode array 1301. The externalcavity 1302 contains block 1320, and the laser beams and beam paths. Theexternal cavity is encompassed by a housing 1350 which has a window forthe transmission of laser beam 1307 along beam path 1307 a.

The diode laser can be any type of diode laser and would include smallsemiconductor lasers, as well as, interband cascade lasers (ICLs);quantum cascade lasers (QCLs).

In the embodiments of FIGS. 1 and 1A the optical coupler is integralwith the stack of filters. In the embodiment of FIG. 2 the opticalcoupler is sperate from the stack of filters.

Turning to FIG. 2 there is shown beam combining assembly 220. Theassembly 220 has a laser diode source 201, (preferably providing laserbeams collimated in the slow axis, the fast axis or both) e.g., an arrayof laser diodes, a laser diode bar, or a collection of individual chips.The laser diode source has individual laser diodes 221 a, 221 b, 221 c,221 d, 221 e. The laser diode source 221 provides laser beams, 222 a,222 b, 222 c, 222 d, 222 e, which travel along laser beam paths that arecoincident with the laser beams. The laser beams have a direction ofpolarization as shown by arrow 227. The laser diodes, e.g., 221 a, eachhave a surface or face, e.g., 223 a, having an AR (anti-reflection)coating. The laser diodes, e.g., 221 a, each have a surface or face,e.g., 224 a, having an HR (high-reflection) coating. The laser beams,e.g., 222 a, travel along their beam paths to a filter stack 225. Thefilter stack 225 has a TIR (total internal reflation) surface, 232, suchthat the laser beam 222 a is directed along the length of the stack andcombined with laser beams 222 b, 222 b, 222 c, 222 d, and 222 e, whichare directed and filtered by wavelength specific filters 228, 229, 230,231, to provide laser beam 226. Each filter has a different wavelength,and preferably a unique wavelength for the others, and can be forexample bandpass, high bandpass, low bandpass and combinations of these,filters. Laser beam 226 travels along its laser beam path to an outputcoupler 233 (R≤∞) that is external to the stack 225, and providesfeedback to the laser sources as defined by the round trip optical pathfrom the laser diodes (221 a,b,c,d,e) through the combiner assembly(220), to the mirror (223) and back through the combiner assembly (220)and finally back to the laser diodes (221 a,b,c,d,e) and which provideslaser beam 235.

Additionally, spectral beam combining can take place simultaneously inthe fast and slow axis within the external cavity as shown in FIG. 3over a broader bandwidth range. Thus, there is a laser assembly 300 thata configuration of five rows 301, 302, 303, 304, 305 of laser diodes,which each row having five laser diodes, e.g., 340 a, which generateindividual laser beams, e.g., 340 b. The laser beams travel along laserbeam paths to a first optical block 320 where the laser beams from eachrow are combined into single beams 311, 312, 313, 314, 315. The combinedlaser beams travel along laser beam paths to a second optical block 330where they are combined into a single laser beam 316, which travelsalong a laser beam path to optic 340 (which can be either a broadbandmirror with the appropriate reflectivity (>30-40%) or a wavelengthselective device such as a narrow band mirror) The transmission functionfor a row may be 3-nm wide, but the overall gain capability of the laserdiode is 20 nm, allowing up to 6 rows to be combined for an additionalincrease in the brightness of the laser system. This cavity transmissionfunction is illustrated in greater detail in FIG. 10.

Turning to FIG. 4 there is shown an embodiment of the transmissionfunctions for four bandpass filters that are used in the combiner blockto define the composite transmission function for the spectral beamcombining cavity with the last reflector being a total internalreflecting surface. The four bandpass filters are shown by transmissionfunctions 401, 402, 403, 404, (Series1, Series2, Series3, Series4respectively) which are combined to provide combined function 410. InFIGS. 4-8 the y-axis is in percent transmission and the x-axis iswavelength in nm.

The overlapping composite transmission function for each of the laserdiodes in the external cavity is shown in FIG. 5 and FIG. 6 for highlycollimated laser sources with collimation on the order of 1 mrad orless. FIG. 5 is a low pass configuration for the case of using the longwavelength edge of the transmission functions to create the passbandsfor each of the laser diode sources. With line 505 for 452.75 nm, line504 for 453.40 nm, line 503 for 454.00 nm, line 502 for 454.60 nm, andline 501 for 455.00 nm. The round trip transmission spectrums for thebeam combiner can best be explained using FIG. 1. The round triptransmission function for the first line 505 is broad because it is theproduct of the broadband reflection characteristics of the TIR surfaceshown as 112 in FIG. 1 and the transmission functions of each of thefollowing filters (401,402,403,404). Since filters are chosen to overlapas shown in FIG. 4, the laser beams see a roundtrip transmissionfunction that allows the light that is shorter in wavelength than theupper wavelength band edges to pass. Peak 504 is narrower than peak 505,because it is the product of the reflection characteristics of filter108 (filter 401 (1-transmission)) and the transmission characteristicsof filter 402, 403 and 404 which results in a pass band that is only0.75 nm wide and is at 453.4 nm. Peak 503 is the product of thereflection characteristics of filter 109 (filter 402) and thetransmission characteristics of filters 403 and 404. This results in apassband that is 0.75 nm wide at 454 nm. Peak 503 is the product of thereflection characteristics of filter 110 (filter 403) and thetransmission characteristics of filter 404. This is the passband at454.6. Peak 502 is the reflection characteristics of filter 111 (filter404) and the bandwidth is defined by the bandwidth of the outputcoupler. The tighter the reflection bandwidth of the output coupler thenarrower peaks 505 and 501 will be. This wavelength peaks for 505 and501 assume that the output coupler is a band reflection filter that is2.25 nm wide. FIG. 6 is a high pass configuration for the case of usingthe short wavelength edge of the transmission functions to create asequence of passbands for each of the laser diodes in the externalcavity. With line 601 for 446.00 nm, line 602 for 447.14 nm, line 603for 447.73 nm, line 604 for 448.33 nm, and line 604 for 448.94 nm. Eachof the combiner filters are arranged at a 45-degree angle within 10micro-radians resulting in each of the laser diode beams overlapping toform a single laser beam with Nx the brightness of the original laserdiode. The resulting transmission functions determines the wavelength,bandwidth and spatial brightness of the laser diodes. The transmissionfunctions are calculated the same way as above but now using the shorterwavelength edge of the filters and allowing the longer wavelengths oflight to pass. Again, 601 and 605 bandwidths are limited by a narrowbandoutput coupler that is only 2.25 nm wide. The 10 micro-radian alignmentis a small deviation from the 1 mrad divergence of the composite beammaking the beam 1.05 mrad in either axis or an M² value of 1.1.

FIGS. 5 and 6 correspond to using single mode laser diodes sources,which beams to be formed with M² values approach 1. However multi-modelaser diodes have a higher divergence in the slow axis, which can be onthe order of 0.25 degrees or less, resulting in a different transmissionfunction for the filters at the higher divergence angles. FIG. 7 andFIG. 8 shows the composite transmission functions for the externalcavity combiner when using the broader transmission functions for alaser source that has a divergence of 0.25 degrees. The filters have allbeen designed to provide a 10-dB decrease in the transmission functionat their overlapping points, which is sufficient to suppress theparasitic lasing outside of the passband regions. In FIG. 7 line 705 isfor 452.75 nm, line 704 is for 453.40 nm, line 703 is for 454.00, line702 is for 454.60 and line 701 is for 455.00. In FIG. 8, line 801 is for446.00 nm, line 802 is for 447.14 nm, line 803 is for 447.73 nm, line804 is for 448.33 nm, line 805 is for 448.94 nm. Similar to theexplanation above for FIG. 5, the outer bands are defined by the outputcoupler used, so for FIG. 7 an output coupler that is 2.25 nm wide willdefine the bandwidth of line 705 and 701. Line 705 is product of thereflection curve for the TIR surface and filters 401, 402, 403, 404.Line 704 is the product of the reflection curve for filter 401(1-Transmission) and the transmission functions for filter 402, 403 and404. Line 703 is the product of the reflection curve for filter 402 andthe transmission functions for filters 403 and 404. Line 702 is theproduct of the reflection curve for filter 403 and the transmissionfunction for filter 404. Line 701 is the product of the reflection curvefor filter 404 and the transmission function of the output coupler whichis not shown in FIG. 4. In FIG. 8 the shorter wavelength edges are usedand similar to the explanation above for FIG. 6, the outer bands aredefined by the output coupler used, so for FIG. 8 an output coupler thatis 2.25 nm wide will define the bandwidth of line 805 and 801. Line 805is product of the reflection curve for the TIR surface and filters 401,402, 403, 404. Line 804 is the product of the reflection curve forfilter 404 (1-Transmission) and the transmission functions for filter401, 402 and 403. Line 803 is the product of the reflection curve forfilter 403 and the transmission functions for filters 401 and 402. Line802 is the product of the reflection curve for filter 402 and thetransmission function for filter 401. Line 801 is the product of thereflection curve for filter 401 and the transmission function of theoutput coupler which is not shown in FIG. 4.

Turning now to a further detailed discussion of embodiments of thepresent invention. As shown in FIGS. 1 and 1A, two or more laser diodeshave high reflective coatings on the back side of the laser diode facetsand anti-reflection coatings on the front side of the laser diodefacets. Optics are used to collimate the light in the fast and slow axisof the laser diodes. Once the laser diode light is collimated, a seriesof optical coatings or volume Bragg gratings (spectral beam combiners)deflect the light at an angle up to 90° with respect to the lightemission direction. The optical coatings or volume Bragg gratings areplaced such that the light emitting from each laser diode is spatiallyoverlapped in the near field and far field simultaneously. The design ofthe optical coatings or volume Bragg gratings results in a passbandthrough the system that determines the lowest loss path for the externalcavity and by definition this results in defining the wavelength each ofthe laser diodes will oscillate on as well as the bandwidth of eachindividual laser diode. Each group of central wavelengths andcorresponding optical bandwidths are mutually exclusive in the opticalspectrum. The external laser cavity is formed by an output couplermirror, a bandwidth-limiting reflective optical coating or volume Bragggrating, of which the bandwidth-limiting optical coating or volume Bragggrating defines the total optical bandwidth of the external lasercavity. As shown in FIG. 1, the output coupler mirror,bandwidth-limiting laser cavity output optical coating or volume Bragggrating can be on the surface/sub-surface of the monolithic opticcontaining the individual optical coatings or volume Bragg gratings.FIG. 2 is identical to FIG. 1 except that the output coupler mirror,bandwidth-limiting laser cavity output optical coating or volume Bragggrating are a separate optic.

The laser cavity can include one or two spectral beam combiners. In thecase of two spectral beam combiners, each specific spectral beamcombiner operates on either the fast or slow axis of the laser diodelight, and both of the spectral beam combiners must operate on theorthogonal axis (with respect to the laser diode emission facet) to eachother. The separate spectral beam combiners operate in serial fashion,such that spectral beam combining is performed on one axis first, andthen on the orthogonal axis afterwards.

The output of the external cavity exhibits a brightness enhancement of Ncompared to a single laser diode, where N is the number of laser diodesin the external laser cavity.

Each individual laser diode will lase at the wavelength of lowest losswithin the transmission function of the composite optic due to theoptical feedback within the external laser cavity, so long as the gainbandwidth of the individual laser diode falls within the transmissionfunction of the composite optical combiner due to the optical feedbackwithin the external laser cavity.

The oscillating bandwidth of the external cavity laser can be modifiedor changed with different types of filters in the external cavity tocontrol the losses of the cavity such that only the lowest losswavelength bands oscillate.

The design of the optical coatings or volume Bragg gratings (bandpassfilters) for a single axis spectrally beam combined external cavity isshown in FIG. 4. The external laser cavity can be arranged to operate inthe low-pass configuration, as shown in FIG. 5, or the high-passconfiguration, as shown in FIG. 6. Both FIG. 5 and FIG. 6 show thefilter transmission function for the fast axis of the laser diode lightor for diode lasers that are single mode in both axes. The case of amultimode laser diode with a modest divergence of 0.25 degrees, FIG. 7shows the transmission functions for the low-pass configuration, andFIG. 8 show the high-pass configuration. Here the transmission lossesare slightly higher due to the divergence angle of the multi-mode laserdiodes. There are many different combinations of beam divergences thatcan be combined, the combiner block is generally configured in terms offree aperture size and channel spacing depending on the divergence ofthe source and the type of source being used, e.g., Individual laserdiodes or a laser diode bar.

FIG. 9 shows an example where the individual bandpass filters of forexample the embodiment of FIG. 4 are designed to overlap such that theproduct of their transmission functions create a comb filter typefunction where ΣΔλ_(BPF)≤Δλ_(OC), where ΣΔλ_(BPF) (901) is the productof the transmission functions of the optical coatings or volume Bragggratings, and Δλ_(OC) (902) is the bandwidth of the output coupler.Defining N as the number of individual laser diode emitters, thebandwidth of each individual bandpass filter is defined such thatΔλ_(BPF)≈Δλ_(OC)/N (903). For a central wavelength of λ_(C), λ_(C)^(N)(Δλ_(BPF) ^(N))−λ_(C) ^(N-1)(Δλ_(BPF) ^(N-1))≥Δλ_(BPF) ^(N-1), whereλ_(C) ^(N)(Δλ_(BPF) ^(N)) is the central wavelength of bandpass filter N(904), λ_(C) ^(N-1)(Δλ_(BPF) ^(N-1)) is the central wavelength ofbandpass filter N-1 (905), and Δλ_(BPF) ^(N-1) is the bandwidth ofbandpass filter N-1 (906). Additionally, λ_(C) ^(N-1)(Δλ_(BPF)^(N-1))−λ_(C) ^(N-2)(Δλ_(BPF) ^(N-2))≥Δλ_(BPF) ^(N-2), and so on alsohold to ensure unique lasing wavelengths for each individual laserdiode.

The single-axis spectrally beam combined external cavity with four laserdiodes can be extended to spectral beam combination in both axes asshown in FIG. 3 by overlapping the transmission functions of one axiswith the transmission functions of a perpendicular axis as shown in FIG.10. In this example, the light out of the individual laser diodes iscollected in the fast and slow axis by separate optics. Each row X oflaser diodes are then spectrally beam combined in the fast axis by abeam combiner similar in construction to FIG. 1 but with a broader combfilter function than the individual rows (e.g., 1050 in FIG. 10corresponds to Row 301 of FIG. 3; and 1051 of FIG. 10 corresponds to Row302 of FIG. 3). Similar to the previous case, individual bandpassfilters for the slow axis are designed to spectral bandwidths such thatthe product of their transmission functions is ΣΔλ_(BPF,S)^(X)≈Δλ_(BPF,F) ^(X), where ΣΔλ_(BPF,S) ^(X) (1001) is the product ofthe transmission functions of the bandpass filters for row X, andΔλ_(BPF,F) ^(X) (1002) is the bandwidth of the following bandpass filterin the fast axis corresponding to the laser diodes spectrally combinedin row X. To combine X rows in the fast axis, the criteria follows thatΔλ_(BPF,F) ^(X)≈Δλ_(OC)/X and ΣΔλ_(BPF,F)≤Δλ_(OC), where ΣΔλ_(BPF,F)(1003) is the product of the transmission functions for the fast axisbandpass filters. To ensure a unique lasing wavelength for eachindividual laser diode, consider M individual laser diodes in each row Xand the additional restrictions follow such that λ_(C) ^(X*M)(Δλ_(BPF,S)^(X*M))−λ_(C) ^(X*M-1)(Δλ_(BPF,S) ^(X*M-1))≥Δλ_(BPF,S) ^(X*(M-1)), whereλ_(C) ^(X*M)(Δλ_(BPF,S) ^(X*M)) (1004) is the central wavelength oflaser diode M in row X, λ_(C) ^(X*M-1)(Δλ_(BPF,S) ^(X*M-1)) (1005) isthe central wavelength of laser diode M-1 in row X, and Δλ_(BPF,S)^(X*M-1) (1006) is the bandwidth of the comb filter defined by theadjacent bandpass filters for laser diode M-1 in row X. It also holdsthat λ_(C) ^(X*M-1)(Δλ_(BPF,S) ^(X*M-1))−λ_(C) ^(X*M-2)(Δλ_(BPF,S)^(X*M-2))≥Δλ_(BPF,S) ^(X*M-2) and so on; λ_(C) ^(X*M-(M-1))(Δλ_(BPF,S)^(X*M-(M-1)))>λ_(C) ^((X-1)*M)(Δλ_(BPF,S) ^((X-1)*M)), λ_(C)^((X-1)*M-(M-1))(Δλ_(BPF,S) ^((X-1)*M-(M-1)))>λ_(C) ^((X-2*M)(Δλ_(BPF,S)^((X-2)*M)) and so on must also hold, where λ_(C)^(X*M-(M-1))(Δλ_(BPF,S) ^(X*M-(M-1))) is the central wavelength of thelowest wavelength bandpass filter in row X (1007) and λ_(C)^((X-1)*M)(Δλ_(BPF,S) ^((X-1)*M)) is the central wavelength of thehighest wavelength bandpass filter in row X-1 (1008). Additionally,λ_(C)(Δλ_(BPF,F) ^(X))−λ_(C)(Δλ_(BPF,F) ^(X-1))≥Δλ_(BPF,F) ^(X-1), whereλ_(C)(Δλ_(BPF,F) ^(X)) (1009) is the central wavelength of the fast axisbandpass filter for row X, λ_(C)(Δλ_(BPF,F) ^(X-1)) (1010) is thecentral wavelength of the fast axis bandpass filter for row X-1, andΔλ_(BPF,F) ^(X-1) (1011) is the bandwidth of the fast axis bandpassfilter for row X-1. It also holds that λ_(C)(Δλ_(BPF,F)^(X-1))−λ_(C)(Δλ_(BPF,F) ^(X-2))≥Δλ_(BPF,F) ^(X-2) and so on. Finally,ΣΔλ_(BPF,F)≈Δλ_(OC), where Δλ_(OC) (1012) is the bandwidth of the outputcoupler to the external laser cavity. Another iteration of this designis such that the fast axis is spectrally beam combined first, followedby spectral beam combination of the slow axis.

For the case where ΣΔλ_(BPF)>Δλ_(OC), the transmission functions, ineither the fast axis, slow axis, or both axes, act like edge filterswhen operating in an external cavity configuration with abandwidth-limiting optical coating or volume Bragg grating acting as theexternal laser cavity output coupler. The restrictions for operating Nindividual emitters at unique wavelengths in either the fast or slowaxis, or both axes simultaneously, are outlined herein.

For a hypothetical single-axis spectrally beam combined external cavitywith four laser diodes, the implementation of the bandpass filters isshown in FIG. 11. The transmission functions of the Individual bandpassfilters are designed to overlap the central wavelength of the rising (orfalling) edge of successive filters is λ_(C)^(RE)(BPF^(N))−λ_(C)(BPF^(N-1))≈(1−1/N)*Δλ_(OC), where λ_(C)^(RE)(BPF^(N)) (1101) is the central wavelength of the leading (orfalling) edge of bandpass filter N, λ_(C) ^(RE)(BPF^(N-1)) (1102) is thecentral wavelength of the leading (or falling) edge of bandpass filterN-1, N is the number of individual emitters in the laser diode cavity,and Δλ_(OC) (1103) is the bandwidth of the output coupler. Additionally,Δλ_(BPF) ^(N)>Δλ(N), Δλ_(BPF) ^(N-1)>Δλ(N-1), and so on, where Δλ_(BPF)^(N) (1104) is the bandwidth of the N^(th) bandpass filter and Δλ(N)(1105) is the bandwidth of any of the N^(th) laser diode. As statedpreviously, the criteria of λ_(C) ^(RE)(BPF^(N))>λ_(C) ^(RE)(BPF^(N-1)),λ_(C) ^(RE)(BPF^(N-1))>λ_(C) ^(RE)(BPF^(N-2)), and so on ensures uniquelasing wavelengths for each individual laser diode. In the low-passconfiguration of FIG. 11, for a series of N laser diodes with λ_(C)^(N)>λ_(C) ^(N-1), λ_(C) ^(N) (1106) will lase between the highestwavelength edge of Δλ_(OC) (1107) and the lowest wavelength edge ofΔλ_(BPF) ^(N) (1108), λ_(C) ^(N-1) (1109) will lase between the lowestwavelength edge of Δλ_(BPF) ^(N) (1108) and the lowest wavelength edgeof Δλ_(BPF) ^(N-1) (1110), and so on.

The single-axis spectrally beam combined external cavity with four laserdiodes (FIGS. 1 and 2) can be extended to spectral beam combination inboth axes using the array configuration depicted in FIG. 3 but withbroader transmission functions for the bandpass filters when combiningthe rows as shown in FIG. 12. In this example, the light out of theindividual laser diodes is collected in the fast and slow axis byseparate optics. Each row X of laser diodes is then spectrally beamcombined in the fast axis by the combiner shown in FIG. 3. Similar tothe previous case, individual bandpass filters for the slow axis aredesigned to spectral bandwidths such that the sum of their spectralbandwidths is ΣΔλ_(BPF,S) ^(X)>Δλ_(BPF,F) ^(X), where ΣΔλ_(BPF,S) ^(X)(1201) is the sum of the spectral bandwidth of the bandpass filters forrow X, and Δλ_(BPF,F) ^(X) (1202) is the bandwidth of the followingbandpass filter in the fast axis corresponding to the laser diodesspectrally combined in row X. To combine X rows in the fast axis, thecriteria follows that Δλ_(BPF,F) ^(X)≥Δλ_(OC)/X and ΣΔλ_(BPF,F)≥Δλ_(OC),where ΣΔλ_(BPF,F) (1203) is the sum of the bandwidths of the fast axisbandpass filters and Δλ_(OC) (1204) is the bandwidth of the outputcoupler. To ensure a unique lasing wavelength for each individual laserdiode, consider M individual laser diodes in each row X and theadditional restrictions follow such that λ_(C) ^(RE)(Δλ_(BPF,S)^(X*M))>λ_(C) ^(RE)(Δλ_(BPF,S) ^(X*M-1)), λ_(C) ^(RE)(Δλ_(BPF,S)^(X*M-1))>λ_(C) ^(RE)(Δλ_(BPF,S) ^(X*M-2)) and so on, where λ_(C)^(RE)(Δλ_(BPF,S) ^(X*M)) (1205) is the central wavelength of the risingedge of the slow axis bandpass filter M in row X, λ_(C) ^(RE)(Δλ_(BPF,S)^(X*M-1)) (1206) is the central wavelength of the rising edge of theslow axis bandpass filter M-1 in row X, and so on. It also holds thatλ_(C)(X*M)>λ_(C)(X*M-1)>λ_(C)(X*M-2) and so on, where λ_(C)(X*M) (1207)is the central wavelength for laser diode X*M, λ_(C)(X*M-1) (1208) isthe central wavelength for laser diode X*M-1, and so on. Additionalcriteria defines λ_(C)(X*M-(M-1))>λ_(C)((X-1)*M),λ_(C)((X-1)*M-(M-1))>λ_(C)((X-2)*M) and so on must also hold, whereλ_(C)(X*M-(M-1)) is the central wavelength of the lowest wavelengthlaser diode in row X (1209) and λ_(c)((X-1)*M) is the central wavelengthof the highest wavelength laser diode in row X-1 (1210).

Additionally, λ_(C)(Δλ_(BPF,F) ^(X))>λ_(C)(Δλ_(BPF,F)^(X-1))>λ_(C)(Δλ_(BPF,F) ^(X-2)) and so on, where λ_(C)(Δλ_(BPF,F) ^(X))(1211) is the central wavelength of the fast axis bandpass filter forrow X, λ_(C)(Δλ_(BPF,F) ^(X-1)) (1212) is the central wavelength of thefast axis bandpass filter for row X-1. Finally, ΣΔλ_(BPF,F)≥Δλ_(OC),where Δλ_(OC) (1204) is the bandwidth of the output coupler to theexternal laser cavity. As shown in FIG. 12, for a series of X*M laserdiodes with λ_(C)(X*M)>λ_(C)(X*M-1), λ_(C)(X*M) (1207) will lase betweenthe highest wavelength edge of Δλ_(OC) (1213) and the lowest wavelengthedge of Δλ_(BPF,S) ^(X*M) (1214), λ_(C)(X*M-1) (1208) will lase betweenthe lowest wavelength edge of Δλ_(BPF,S) ^(X*M) (1214) and the lowestwavelength edge of Δλ_(BPF,S) ^(X*M-1) (1215), and so on. The finalparameter is that λ_(C)(1) (1216) will lase between the highestwavelength edge of Δλ_(BPF,S) ¹ (1217) and the lowest wavelength of theoutput coupler (1218). Another iteration of this design is such that thefast axis is spectrally beam combined first, followed by spectral beamcombination of the slow axis.

In embodiments the brightness of the combined laser beam, e.g., 1307,where brightness is defined as the combined power divided by theaperture-divergence product, is n-times (“n”×) brighter than any singlediode used in the collection of diodes for the laser assembly, e.g., thediode array, an array of laser diodes, a laser diode bar, or acollection of individual chips. Thus, the combined beam can be about1.5×, about 10×, about 25×, about 50×, about 150×, about 300×, fromabout 1.5× to about 300×, from about 100× to about 150×, and all valueswithin these ranges, as well as greater than 5×, greater than 50×,greater than 100× brighter than any single laser diode used in thecollection of laser diodes. In particular, this n-times increase inbrightness is in embodiments of laser beams in the blue, green,blue-green and visible wavelengths.

Table 1 shows the power, brightness and performance that can be achievedwith 140-2.5-Watt laser diodes in a two dimensional spectrally beamcombined configuration. This table illustrates how the power andbrightness of laser systems based on a building block 350-Watt modulescales to the multi-kW power level using fiber combiners to launch intoa process fiber.

TABLE 1 Modules Output Power BPP (mm-mrad) 1 350 5 2 700 13 3 1050 14 41400 15 5 1750 17 6 2100 19 7 2450 19 8 2800 21 9 3150 23 10 3500 24 113850 25 12 4200 27 13 4550 27 14 4900 28 15 5250 29 16 5600 30 17 595031 18 6300 32

The same modules may also be combined in free space which conservesbrightness but makes module replacement slightly more complicated. Thepower and beam parameter products that can be achieved with free spacecombination are shown in Table 2.

TABLE 2 Output Power Process Fiber (microns) BPP (mm-mrad) 350 45 5 70090 9 1050 97 10 1400 109 11 1750 122 13 2100 135 14 2450 135 14 2800 14916 3150 163 17 3500 172 18 3850 181 19 4200 191 20 4550 195 20 4900 20321 5250 208 22 5600 216 23 5950 219 23 6300 230 24

The following table illustrates the effect of using a higher power bluelaser diode with each device being approximately 6.5 Watts. The basemodule of 140 laser diodes is now approximately 900 Watts and thesemodules are combined through fiber combiners to build high power, highbrightness blue laser diode systems. As shown in Table 3.

TABLE 3 Number of Modules Output Power BPP (mm-mrad) 1 882 5 2 1,764 133 2,646 14 4 3,528 15 5 4,410 17 6 5,292 19 7 6,174 19 8 7,056 21 97,938 23 10 8,820 24 11 9,702 25 12 10,584 27 13 11,466 27 14 12,348 2815 13,230 29 16 14,112 30 17 14,994 31 18 15,876 32

EXAMPLES

The following examples are provided to illustrate various embodiments ofthe present laser systems and operations and including laser systems forwelding components, including components in electronic storage devices.These examples are for illustrative purposes, may be prophetic, andshould not be viewed as, and do not otherwise limit the scope of thepresent inventions.

Example 1

An embodiment of a high power, high brightness laser system has twoindividual high power laser diodes. The diodes can be from about 2 W to10 W. A preferable diode laser is 10 Watts with a stripe width <100microns which is achievable in the infrared. The diodes in the bluewavelength range can be about 2.5 W to 6.5 Watts with a stripe widthless than 40 microns. The system has a common external cavity shared bythe individual high-power laser diodes. The system can be scaled, havingthree, four, ten, a dozen and more laser diodes (e.g., FIG. 3). Thereare further collimating optics for creating parallel beams from each ofthe high-power laser diodes. The system has a beam combination optics inthe common external cavity which determines the wavelength of each laserdiode and each laser diode is aligned to be co-linear and overlapping inspace. The system provides a spatial brightness of the laser source fromthe system that is n-times the brightness of a single laser diode wherebrightness is defined as the combined power divided by theaperture-divergence product. A two-dimensional array that completelyfills the available gain curve for the laser diode can produce a sourcethat is 30× the brightness of a single laser diode (e.g., FIG. 3). Evenhigher spatial brightness is feasible by selecting laser diodes thathave a different gain spectrum outside of the gain spectrum of the first30 laser diodes making it feasible to increase the spatial brightness ofthe laser diode source by another factor of 2 to 60× the spatialbrightness of a single device. This can be expanded over a wide rangedepending on the final bandwidth of the laser source desired. Apractical range is ˜100 nm, e.g., 405-505 nm, for a total spatialbrightness increase approaching 150×.

Example 2

In an embodiment of the external cavity the beam combination optic is aset of optical filters that are used at the edge of either the low passor high pass end of the spectrum for a bandpass filter.

Example 3

In the embodiment of the system of Example 1, the external cavity laseris operating in the 400-500 nm range with an output power of >1 Watt anda beam parameter product of 0.1 mm-mrad or larger.

Example 4

In an embodiment the external cavity laser is operating in the 500-600nm range with an output power of >1 Watt and a beam parameter product of0.1 mm-mrad or larger.

Example 5

In an embodiment the external cavity laser is operating in the 720-800nm range with an output power of >1 Watt and a beam parameter product of0.1 mm-mrad or larger.

Example 6

In an embodiment of the external cavity laser is operating in the800-900 nm range with an output power of >1 Watt and a beam parameterproduct of 0.1 mm-mrad or larger.

Example 7

In an embodiment of the external cavity laser is operating in the900-1200 nm range with an output power of >1 Watt and a beam parameterproduct of 0.1 mm-mrad or larger.

Example 8

In an embodiment of the external cavity laser is operating in the 1200nm-1120 nm range with an output power of >1 Watt and a beam parameterproduct of 0.1 mm-mrad or larger.

Example 9

In an embodiment of the external cavity laser is operating in the1400-1500 nm range with an output power of >1 Watt and a beam parameterproduct of 0.1 mm-mrad or larger.

Example 10

In an embodiment of the external cavity laser is operating in the1500-2200 nm range with an output power of >1 Watt and a beam parameterproduct of 0.1 mm-mrad or larger.

Example 11

In an embodiment the external cavity laser based on interband cascadelasers described in (1) operating in the 2200-3000 nm range with anoutput power of >1 Watt and a beam parameter product of 0.1 mm-mrad orlarger.

Example 12

In an embodiment the external cavity laser based on quantum cascadelasers described in (1) operating in the 3000 nm-4000 nm range with anoutput power of >1 Watt and a beam parameter product of 0.1 mm-mrad orlarger.

Example 13

In an embodiment the external cavity of the system has a beamcombination optic that is a set of Volume Bragg Grating filters. Thesefilters can have a very narrow reflection spectrum and do not rely onthe difference between two filters like the dichroic combiner approachto achieve the same performance. In addition, these Bragg Gratings canbe written directly into a single piece of photosensitive glass andeliminate the need for post polishing and alignment of the individualblocks. One or more of the volume Bragg gratings redirects a portion ofthe optical spectrum from an individual laser diode to be collinear withthe previous laser diode in the array. In this manner the brightness ofthe sum of the individual laser diode beams after being directed by thevolume Bragg gratings(s) is N times brighter than that of an individuallaser diode beam, with N being the number of laser diodes beingcombined. In this manner in a series of N volume Bragg gratings, thepoints of maximum transmission through volume Bragg grating N coincidewith the N-1, N-2, N-3, . . . 1^(st) peaks of the lasing spectra of theN-1, N-2, N-3, . . . 1^(st) laser diodes, while simultaneously providingmaximum beam deflection of laser diode N. This embodiment can beutilized in the embodiment of Example 1 and other Examples. Anembodiment of which is shown in FIG. 1A

Example 14

In an embodiment of the laser system, for example a system of Example13, the laser system operates on the slow axis of the emitted laserdiode light and the TE-mode of individual reflection volume Bragggrating(s).

Example 15

In an embodiment of the laser system, for example a system of Example13, the laser system operates on the fast axis of the emitted laserdiode light and the TE-mode of individual reflection volume Bragggrating(s).

Example 16

In an embodiment of the laser system, for example a system of Example13, the laser system that operates on the slow axis of the emitted laserdiode light and the TM-mode of individual reflection volume Bragggrating(s).

Example 17

In an embodiment of the laser system, for example a system of Example13, the laser system that operates on the fast axis of the emitted laserdiode light and the TM-mode of individual reflection volume Bragggrating(s).

Example 18

In an embodiment of the laser system, for example a system of Example13, the laser system operates on the slow axis of the emitted laserdiode light and the TE-mode of individual transmission volume Bragggrating(s).

Example 19

In an embodiment of the laser system, for example a system of Example13, the laser system operates on the fast axis of the emitted laserdiode light and the TE-mode of individual transmission volume Bragggrating(s).

Example 20

In an embodiment of the laser system, for example a system of Example13, the laser system operates on the slow axis of the emitted laserdiode light and the TM-mode of individual transmission volume Bragggrating(s).

Example 21

In an embodiment of the laser system, for example a system of Example13, the laser system operates on the fast axis of the emitted laserdiode light and the TM-mode of individual transmission volume Bragggrating(s).

Example 22

In an embodiment of the laser system, for example a system of Example13, the laser system operates on the slow axis of the emitted laserdiode light and the TE-mode of individual reflection volume Bragggrating(s) fabricated in a single piece of material.

Example 23

In an embodiment of the laser system, for example a system of Example13, the laser system operates on the fast axis of the emitted laserdiode light and the TE-mode of individual reflection volume Bragggrating(s) fabricated in a single piece of material.

Example 24

In an embodiment of the laser system, for example a system of Example13, the laser system operates on the slow axis of the emitted laserdiode light and the TM-mode of individual reflection volume Bragggrating(s) fabricated in a single piece of material.

Example 25

In an embodiment of the laser system, for example a system of Example13, the laser system operates on the fast axis of the emitted laserdiode light and the TM-mode of individual reflection volume Bragggrating(s) fabricated in a single piece of material.

Example 26

In an embodiment of the laser system, for example a system of Example13, the laser system operates on the slow axis of the emitted laserdiode light and the TE-mode of individual transmission volume Bragggrating(s) fabricated in a single piece of material.

Example 27

In an embodiment of the laser system, for example a system of Example13, the laser system operates on the fast axis of the emitted laserdiode light and the TE-mode of individual transmission volume Bragggrating(s) fabricated in a single piece of material.

Example 28

In an embodiment of a system, the system has one or more opticalcoatings that redirects a portion of the power from an individual laserdiode at an angle up to 90° with respect to the laser diode output lightpropagation direction after collimation. In this system, the opticalpropagation directions in the near-field and far-field are identicalamong two or more individual laser diodes after being redirected by theoptical coating(s). In this manner the brightness of the sum of theindividual laser diode beams after being directed by the opticalcoating(s) is N times brighter than that of an individual laser diodebeam, with N being the number of laser diodes being combined. Thus, in aseries of N optical coatings, the points of maximum transmission throughoptical coating N coincide with the N-1, N-2, N-3, . . . 1^(st) peaks ofthe lasing spectra of the N-1, N-2, N-3, . . . 1^(st) laser diodes,while simultaneously providing maximum beam deflection of laser diode N.This embodiment can be utilized in the embodiment of Example 1, andother Examples, including the embodiment of FIG. 1.

Example 29

In an embodiment a laser source has one or more volume Bragg gratings.The output light direction from the optical coating(s) is 90° withrespect to the output light direction from the volume Bragg grating(s).The brightness of the sum of the individual laser diode beams afterbeing combined by the volume Bragg gratings(s) and the opticalcoating(s) is N times brighter than that of an individual laser diodebeam, with N is the number of individual laser diode beams, C is thenumber of optical coating(s), and N/C is the number of individual laserdiode beams being combined by the volume Bragg grating(s) as groups. Theoptical bandwidths of each individual combination of laser diodescombined by the volume Bragg grating(s) are mutually exclusive.

Thus, given an arbitrary central blue wavelength λ_(c), the opticalbandwidth from volume Bragg grating M=Δλ_(M), the optical bandwidth ofvolume Bragg grating M-1=Δλ_(M-1) such that Δλ_(M-1)≈Δλ_(M) andλ_(c)(Δλ_(M))−λ_(c)(Δλ_(M-1))≥Δλ_(M-1), the optical bandwidth fromvolume Bragg grating M-2=Δλ_(M-2), such that Δλ_(M-2)≈Δλ_(M) andλ_(c)(Δλ_(M-1))−λ_(c)(Δλ_(M-2))≥Δλ_(M-2), and so on.

Further, given an arbitrary central blue wavelength λ_(c), the opticalbandwidth from optical coating X=Δλ_(X), the optical bandwidth ofoptical coating X-1=Δλ_(X-1) such that Δλ_(X-1)≈Δλ_(X) andλ_(c)(Δλ_(X))−λ_(c)(Δλ_(X-1))≥Δλ_(X-1), the optical bandwidth fromoptical coating X-2=Δλ_(X-2), such that Δλ_(X-2)≈Δλ_(X) andλ_(c)(Δλ_(X-1))−λ_(c)(Δλ_(X-2))≥Δλ_(X-2), and so on.

Further, given an arbitrary central blue wavelength λ_(c), the opticalbandwidth from optical coating X=Δλ_(X) and the optical bandwidth of thesum of volume Bragg grating(s) ΣΔλ_(M1) such that Δλ_(X)≥ΣΔλ_(M1) andλ_(c)(Δλ_(X))≈λ_(c)(ΣΔλ_(M1)), the optical bandwidth from opticalcoating X-1=Δλ_(X-1) and the optical bandwidth of the sum of volumeBragg grating(s) ΣΔλ_(M2) such that Δλ_(X-1)≥ΣΔλ_(M2) andλ_(c)(Δλ_(X-1))≈λ_(c)(ΣΔλ_(M2)), and so on.

Example 30

In an embodiment the system has one or more optical coatings. The outputlight direction from the volume Bragg grating(s) is 90° with respect tothe output light direction from the optical coating(s). The brightnessof the sum of the individual laser diode beams after being combined bythe volume Bragg gratings(s) and the optical coating(s) is N timesbrighter than that of an individual laser diode beam, with N is thenumber of individual laser diode beams, B is the number of volume Bragggrating(s), and N/B is the number of individual laser diode beams beingcombined by the optical coating(s) as groups. The optical bandwidths ofeach individual combination of laser diodes combined by the volume Bragggrating(s) are mutually exclusive.

The optical bandwidths of each individual combination of laser diodescombined by optical coating(s) are mutually exclusive.

Thus, given an arbitrary central blue wavelength λ_(c), the opticalbandwidth from volume Bragg grating M=Δλ_(M), the optical bandwidth ofvolume Bragg grating M-1=Δλ_(M-1) such that Δλ_(M-1)≈Δλ_(M) andλ_(c)(Δλ_(M))−λ_(c)(Δλ_(M-1))≥Δλ_(M-1), the optical bandwidth fromvolume Bragg grating M-2=Δλ_(M-2), such that Δλ_(M-2)≈Δλ_(M) andλ_(c)(Δλ_(M-1))−λ_(c)(Δλ_(M-2))≥Δλ_(M-2), and so on.

Further, given an arbitrary central blue wavelength λ_(c), the opticalbandwidth from optical coating X=Δλ_(X), the optical bandwidth ofoptical coating X-1=Δλ_(X-1) such that Δλ_(X-1)≈Δλ_(X) andλ_(c)(Δλ_(X))−λ_(c)(Δλ_(X-1))≥Δλ_(X-1), the optical bandwidth fromoptical coating X-2=Δλ_(X-2), such that Δλ_(X-2)≈Δλ_(X) andλ_(c)(Δλ_(X-1))−λ_(c)(Δλ_(X-2))≥Δλ_(X-2), and so on.

Further, given an arbitrary central blue wavelength λ_(c), the opticalbandwidth from volume Bragg grating X=Δλ_(X) and the optical bandwidthof the sum of coatings(s) ΣΔλ_(M1) such that Δλ_(X)≥ΣΔλ_(M1) andλ_(c)(Δλ_(X))≈λ_(c)(ΣΔλ_(M1)), the optical bandwidth from volume Bragggrating X-1=Δλ_(X-1) and the optical bandwidth of the sum of opticalcoating(s) ΣΔλ_(M2) such that Δλ_(X-1)≥ΣΔλ_(M2) andλ_(c)(Δλ_(X-1))≈λ_(c)(ΣΔλ_(M2)), and so on.

Example 30A

The embodiments of Example 30 are utilized in the embodiments of theother Examples.

Example 31

In an embodiment of a laser system, the system the output lightdirection from the following volume Bragg grating(s) is 90° with respectto the output light direction from the previous volume Bragg grating(s).The brightness of the sum of the individual laser diode beams afterbeing combined by the volume Bragg gratings(s) is N times brighter thanthat of an individual laser diode beam, with N is the number ofindividual laser diode beams, B is the number of secondary volume Bragggrating(s), and N/B is the number of individual laser diode beams beingcombined by the primary volume Bragg grating(s) as groups.

The optical bandwidths of each individual combination of laser diodescombined by the primary volume Bragg grating(s) are mutually exclusive.The optical bandwidths of each individual combination of laser diodescombined by the secondary volume Bragg grating(s) are mutuallyexclusive.

Thus, given an arbitrary central blue wavelength λ_(c), the opticalbandwidth from the primary volume Bragg grating M=Δλ_(M), the opticalbandwidth of the primary volume Bragg grating M-1=Δλ_(M-1) such thatΔλ_(M-1)≈Δλ_(M) and λ_(c)(Δλ_(M))−λ_(c)(Δλ_(M-1))≥Δλ_(M-1), the opticalbandwidth from the primary volume Bragg grating M-2=Δλ_(M-2), such thatΔλ_(M-2)≈Δλ_(M) and λ_(c)(Δλ_(M-1))−λ_(c)(Δλ_(M-2))≥Δλ_(M-2), and so on.

Further, given an arbitrary central blue wavelength λ_(c), the opticalbandwidth from the secondary volume Bragg grating X=Δλ_(X), the opticalbandwidth of secondary volume Bragg grating X-1=Δλ_(X-1) such thatΔλ_(X-1)≈Δλ_(X) and λ_(c)(Δλ_(X))−λ_(c)(Δλ_(X-1))≥Δλ_(X-1), the opticalbandwidth from secondary volume Bragg grating X-2=Δλ_(X-2), such thatΔλ_(X-2)≈Δλ_(X) and λ_(c)(Δλ_(X-1))−λ_(c)(Δλ_(X-2))≥Δλ_(X-2), and so on.

Additionally, given an arbitrary central blue wavelength λ_(c), theoptical bandwidth from the secondary volume Bragg grating X=Δλ_(X) andthe optical bandwidth of the sum of the primary volume Bragg gratingsΣΔλ_(M1) such that Δλ_(X)≥ΣΔλ_(M1) and λ_(c)(Δλ_(X))≈λ_(c)(ΣΔλ_(M1)),the optical bandwidth from the secondary volume Bragg gratingX-1=Δλ_(X-1) and the optical bandwidth of the sum of the primary volumeBragg gratings Δλ_(M2) such that Δλ_(X-1)≥ΣΔλ_(M2) andλ_(c)(Δλ_(X-1))≈λ_(c)(ΣΔλ_(M2)), and so on.

Example 31A

The embodiments of Example 31 are utilized in the embodiments of theother Examples.

Example 32

In an embodiment a laser system has one or more optical coatings(s). Theoutput light direction from the following optical coating(s) is 90° withrespect to the output light direction from the previous opticalcoating(s). The brightness of the sum of the individual laser diodebeams after being combined by the optical coating(s) N times brighterthan that of an individual laser diode beam, with N is the number ofindividual laser diode beams, C is the number of secondary opticalcoating(s), and N/C is the number of individual laser diode beams beingcombined by the primary optical coatings(s) as groups.

The optical bandwidths of each individual combination of laser diodescombined by the primary optical coatings(s) are mutually exclusive. Theoptical bandwidths of each individual combination of laser diodescombined by the secondary optical coating(s) are mutually exclusive.

Thus, given an arbitrary central blue wavelength λ_(c), the opticalbandwidth from the primary optical coating M=Δλ_(M), the opticalbandwidth of the primary optical coating M-1=Δλ_(M-1) such thatΔλ_(M-1)≈Δλ_(M) and λ_(c)(Δλ_(M))−λ_(c)(Δλ_(M-1))≥Δλ_(M-1), the opticalbandwidth from the primary optical coating M-2≈Δλ_(M-2), such thatΔλ_(M-2)=Δλ_(M) and λ_(c)(Δλ_(M-1))−λ_(c)(Δλ_(M-2))≥Δλ_(M-2), and so on.

Further, given an arbitrary central blue wavelength λ_(c), the opticalbandwidth from the secondary optical coating X=Δλ_(X), the opticalbandwidth of secondary optical coating X-1=Δλ_(X-1) such thatΔλ_(X-1)≈Δλ_(X) and λ_(c)(Δλ_(X))−λ_(c)(Δλ_(X-1))≥Δλ_(X-1), the opticalbandwidth from secondary optical coating X-2=Δλ_(X2), such thatΔλ_(X-2)≈Δλ_(X) and λ_(c)(Δλ_(X-1))−λ_(c)(Δλ_(X-2))≥Δλ_(X-2), and so on.

Additionally, given an arbitrary central blue wavelength λ_(c), theoptical bandwidth from the secondary coating X=Δλ_(X) and the opticalbandwidth of the sum of the primary optical coatings ΣΔλ_(M1) such thatΔλ_(X)≥ΣΔλ_(M1) and λ_(c)(Δλ_(X))≈λ_(c)(ΣΔλ_(M1)), the optical bandwidthfrom the secondary optical coating X-1=Δλ_(X-1) and the opticalbandwidth of the sum of the primary optical coatings ΣΔλ_(M2) such thatΔλ_(X-1)≥ΣΔλ_(M2) and λ_(c)(Δλ_(X-1))≈λ_(c)(ΣΔλ_(M2)), and so on.

Example 32A

The embodiments of Example 32 are utilized in the embodiments of theother Examples.

It is noted that there is no requirement to provide or address thetheory underlying the novel and groundbreaking processes, systems,materials, performance or other beneficial features and properties thatare the subject of, or associated with, embodiments of the presentinventions. Nevertheless, various theories are provided in thisspecification to further advance the art in this area. The theories putforth in this specification, and unless expressly stated otherwise, inno way limit, restrict or narrow the scope of protection to be affordedthe claimed inventions. These theories many not be required or practicedto utilize the present inventions. It is further understood that thepresent inventions may lead to new, and heretofore unknown theories toexplain the function-features of embodiments of the methods, articles,materials, devices and system of the present inventions; and such laterdeveloped theories shall not limit the scope of protection afforded thepresent inventions.

The various embodiments of systems, equipment, techniques, methods,activities and operations set forth in this specification may be usedfor various other activities and in other fields in addition to thoseset forth herein. Additionally, these embodiments, for example, may beused with: other equipment or activities that may be developed in thefuture; and with existing equipment or activities which may be modified,in-part, based on the teachings of this specification. Further, thevarious embodiments set forth in this specification may be used witheach other in different and various combinations. Thus, for example, theconfigurations provided in the various embodiments of this specificationmay be used with each other; and the scope of protection afforded thepresent inventions should not be limited to a particular embodiment,configuration or arrangement that is set forth in a particularembodiment, example, or in an embodiment in a particular Figure.

The invention may be embodied in other forms than those specificallydisclosed herein without departing from its spirit or essentialcharacteristics. The described embodiments are to be considered in allrespects only as illustrative and not restrictive.

1-71. (canceled)
 72. A method of processing a material using a highpower, high brightness laser system, the method comprising: a.generating a laser beam from a laser system comprising: i. a pluralityof laser diodes, each having a power of not less than 0.25 W, whereineach of the plurality of laser diodes is configured to provide a laserbeam along a laser beam path; ii. a collimating optic in the laser beampaths for creating parallel beams from each of the plurality of laserdiodes; iii. a beam combination optic in a common external cavity and inthe laser beam paths; wherein the beam combination optic aligns eachlaser beam path from the plurality of laser diodes to be co-linear andoverlapping in space, whereby a composite output laser beam is provided;and, iv. the spatial brightness of the composite output laser beam is ntimes the brightness of any single laser diode in the plurality of laserdiodes, where spatial brightness is defined as the combined powerdivided by the aperture-divergence product; b. directing the laser beamat a material to be processed; and, c. processing the material.
 73. Themethod of claim 72, wherein generating the laser beam comprisingoperating the laser system in the 400-500 nm range with an output powerof not less than 10 Watts and a beam parameter product of 0.1 mm-mrad orlarger.
 74. The method of claim 72, wherein generating the laser beamcomprising operating the laser system in the 500-600 nm range with anoutput power of not less than 10 Watts and a beam parameter product of0.1 mm-mrad or larger.
 75. The method of claim 72, wherein generatingthe laser beam comprising operating the laser system in the 720-800 nmrange with an output power not less than 10 Watts and a beam parameterproduct of 0.1 mm-mrad or larger.
 76. The method of claim 72, 73, 74, or75, wherein n is not less than
 5. 77. The method of claim 72, 73, 74, or75, wherein the beam combination optic comprises a plurality of volumeBragg grating filters; wherein a first volume Bragg gratings isconfigured to redirect a portion of the optical spectrum of a firstlaser beam from a first laser diode in the plurality of laser diodes tobe collinear with the a laser beam from a second laser diode in theplurality of laser diodes; and wherein n is not less than
 5. 78. Themethod of claim 72, 73, 74, or 75, wherein the plurality of laser diodesconsists of N diodes; wherein each of the N diodes defines a 1st peak ofa lasing spectra; wherein the beam combining optic consists of aplurality of volume Bragg grating consisting of N-1 volume Bragg gratingfilters; the volume Bragg gratings and N-1 of the laser diodesconfigured in an optical association such that points of maximumtransmission through each volume Bragg grating of the plurality ofvolume Bragg gratings coincide with the N-1, N-2 to N-(N-1) 1^(st) peakof N-1 laser diodes in the plurality of laser diodes; whereby the N isequal to n.
 79. The method of claim 72, 73, 74, or 75, wherein thematerial comprises a metal selected from the group consisting of such ascopper, gold, aluminum, steel, nickel, powder, powder, copper allow,aluminum alloy, titanium alloy, and nickel alloy.
 80. The method ofclaim 72, 73, 74, or 75, wherein processing the material comprises oneor more of processing copper to aluminum, copper to steel, gold toaluminum, gold to steel, or copper to nickel.
 81. The method of claim72, 73, 74, or 75, wherein the material comprises one or more of copper,gold, aluminum, steel, nickel, copper powder, aluminum powder, copperallow, aluminum alloy, titanium alloy, or nickel alloy.
 82. The methodof claim 72, 73, 74, or 75, wherein the process comprises a methodselected from the group consisting of welding, soldering, smelting,joining, annealing, softening, tackifying, resurfacing, peening,thermally treating, fusing, sealing, and stacking.
 83. The method ofclaim 72, 73, 74, or 75, wherein the process comprises one or more ofwelding, soldering, smelting, joining, annealing, softening, tackifying,resurfacing, peening, thermally treating, fusing, sealing, or stacking.84. The method of claim 72, 73, 74, or 75, wherein the process compriseswelding or joining; and wherein the material comprises copper, gold,steel, aluminum, or nickel.
 85. A method of processing a material usinga high power, high brightness laser system, the method comprising: a.generating a laser beam from a laser system comprising: i. a pluralityof N laser diodes, wherein each of the plurality of laser diodes isconfigured to provide a laser beam along a laser beam path at a laserbeam power; wherein the laser beam path comprises an output propagationdirection; ii. a collimating optic in the output propagation directionlaser beam paths for creating parallel beams from each of the pluralityof laser diodes; iii. a beam combination optic in the output propagationdirection laser beam paths; iv. wherein the beam combining opticcomprises N-1 optical elements comprising optical coatings, whereby theoptical elements redirect a portion of the optical spectrum of the laserbeam from a laser diode in the plurality of laser diodes at an angle upto 90-00 with respect to the output propagation direction laser beampaths, thereby providing a composite output laser beam defining abrightness; and, v. whereby the brightness of the composite output laserbeam is n times the brightness of any single laser diode in theplurality of laser diodes, where brightness is defined as the combinedpower divided by the aperture-divergence product; and, b. directing thelaser beam at a material to be processed; and, c. processing thematerial.
 86. The method of claim 85, wherein generating the laser beamcomprising operating the laser system in the 400-500 nm range with anoutput power of not less than 10 Watts and a beam parameter product of0.1 mm-mrad or larger.
 87. The method of claim 85, wherein generatingthe laser beam comprising operating the laser system in the 500-600 nmrange with an output power of not less than 10 Watts and a beamparameter product of 0.1 mm-mrad or larger.
 88. The method of claim 85,wherein generating the laser beam comprising operating the laser systemin the 720-800 nm range with an output power not less than 10 Watts anda beam parameter product of 0.1 mm-mrad or larger.
 89. The method ofclaim 85, 86, 87, or 88, wherein n is not less than
 5. 90. The method ofclaim 85, 86, 87, or 88, wherein the beam combination optic comprises aplurality of volume Bragg grating filters; wherein a first volume Bragggratings is configured to redirect a portion of the optical spectrum ofa first laser beam from a first laser diode in the plurality of laserdiodes to be collinear with the a laser beam from a second laser diodein the plurality of laser diodes; and wherein n is not less than
 5. 91.The method of claim 85, 86, 87, or 88, wherein the plurality of laserdiodes consists of N diodes; wherein each of the N diodes defines a 1stpeak of a lasing spectra; wherein the beam combining optic consists of aplurality of volume Bragg grating consisting of N-1 volume Bragg gratingfilters; the volume Bragg gratings and N-1 of the laser diodesconfigured in an optical association such that points of maximumtransmission through each volume Bragg grating of the plurality ofvolume Bragg gratings coincide with the N-1, N-2 to N-(N-1) 1^(st) peakof N-1 laser diodes in the plurality of laser diodes; whereby the N isequal to n.
 92. The method of claim 85, 86, 87, or 88, wherein thematerial comprises a metal selected from the group consisting of such ascopper, gold, aluminum, steel, nickel, powder, powder, copper allow,aluminum alloy, titanium alloy, and nickel alloy.
 93. The method ofclaim 85, 86, 87, or 88, wherein processing the material comprises oneor more of processing copper to aluminum, copper to steel, gold toaluminum, gold to steel, or copper to nickel.
 94. The method of claim85, 86, 87, or 88, wherein the material comprises one or more of copper,gold, aluminum, steel, nickel, copper powder, aluminum powder, copperallow, aluminum alloy, titanium alloy, or nickel alloy.
 95. The methodof claim 85, 86, 87, or 88, wherein the process comprises a methodselected from the group consisting of welding, soldering, smelting,joining, annealing, softening, tackifying, resurfacing, peening,thermally treating, fusing, sealing, and stacking.
 96. The method ofclaim 85, 86, 87, or 88, wherein the process comprises one or more ofwelding, soldering, smelting, joining, annealing, softening, tackifying,resurfacing, peening, thermally treating, fusing, sealing, or stacking.97. The method of claim 85, 86, 87, or 88, wherein the process compriseswelding or joining; and wherein the material comprises copper, gold,steel, aluminum, or nickel.
 98. A method of processing a material usinga high power, high brightness laser system, the method comprising: a.generating a laser beam from a laser system comprising: i. a pluralityof N laser diodes, wherein each of the plurality of laser diodes isconfigured to provide a laser beam along a laser beam path at a laserbeam power; wherein the laser beam path comprises an output propagationdirection; ii. a collimating optic in the output propagation directionlaser beam paths for creating parallel beams from each of the pluralityof laser diodes; iii. a beam combination optic in the output propagationdirection laser beam paths; iv. wherein the beam combining opticcomprises N-1 optical elements; v. thereby providing a combined outputlaser beam defining a brightness; and, vi. the brightness of the sum ofthe individual laser diode beams after being combined by the beamcombining optic is n times brighter than that of an individual laserdiode beam; wherein n=N or n=N-1, N is the number of individual laserdiode beams; b. directing the laser beam at a material to be processed;and, c. processing the material.
 99. The method of claim 98, whereingenerating the laser beam comprising operating the laser system in the400-500 nm range with an output power of not less than 10 Watts and abeam parameter product of 0.1 mm-mrad or larger.
 100. The method ofclaim 98, wherein generating the laser beam comprising operating thelaser system in the 500-600 nm range with an output power of not lessthan 10 Watts and a beam parameter product of 0.1 mm-mrad or larger.101. The method of claim 98, wherein generating the laser beamcomprising operating the laser system in the 720-800 nm range with anoutput power not less than 10 Watts and a beam parameter product of 0.1mm-mrad or larger.
 102. The method of claim 98, 99, 100, or 101, whereinn is not less than
 5. 103. The method of claim 98, 99, 100, or 101,wherein the material comprises a metal selected from the groupconsisting of such as copper, gold, aluminum, steel, nickel, powder,powder, copper allow, aluminum alloy, titanium alloy, and nickel alloy.104. The method of claim 98, 99, 100, or 101, wherein processing thematerial comprises one or more of processing copper to aluminum, copperto steel, gold to aluminum, gold to steel, or copper to nickel.
 105. Themethod of claim 98, 99, 100, or 101, wherein the material comprises oneor more of copper, gold, aluminum, steel, nickel, copper powder,aluminum powder, copper allow, aluminum alloy, titanium alloy, or nickelalloy.
 106. The method of claim 98, 99, 100, or 101, wherein the processcomprises a method selected from the group consisting of welding,soldering, smelting, joining, annealing, softening, tackifying,resurfacing, peening, thermally treating, fusing, sealing, and stacking.107. The method of claim 98, 99, 100, or 101, wherein the processcomprises one or more of welding, soldering, smelting, joining,annealing, softening, tackifying, resurfacing, peening, thermallytreating, fusing, sealing, or stacking.
 108. The method of claim 98, 99,100, or 101, wherein the process comprises welding or joining; andwherein the material comprises copper, gold, steel, aluminum, or nickel.